Stream slave accel via ESP-NOW with master snapshot cache.

Slaves push BMA456 samples at 16ms when enabled; the master caches per
client and exposes ACCEL_SNAPSHOT and ACCEL_STREAM over UART. goTool adds
dashboard stream controls, HTTP accel-stream routes, and an external
WebSocket API with per-connection receive/interval and slave stream commands.

Co-authored-by: Cursor <cursoragent@cursor.com>

goTool/README.md

@@ -25,7 +25,7 @@ go run . -port /dev/ttyUSB0 clients
 | `version` | `0x03` | Prints `version` and `git_hash` from firmware |
 | `clients` | `0x04` | Lists slaves registered on the master via ESP-NOW |
 | `deadzone` | `0x06` | Get/set accelerometer deadzone LSB (`-set`, `-value`, `-client`, `-all`) |
-| `accel` | `0x18` | Read current BMA456 XYZ (raw LSB, ±2g); alias `accel-read` |
+| `accel` | `0x18` | Cached slave accel snapshot from master (`ACCEL_SNAPSHOT`); alias `accel-read` |
 | `unicast-test` | `0x07` | Sends ESP-NOW unicast test to one slave (`-client`, `-seq`) |
 | `test` | — | Run an automated scenario (JSON configs under `testdata/`) |
 | `serve` | — | Web dashboard at `http://localhost:8080` (WebSocket live updates) |
@@ -62,11 +62,91 @@ Polls the master over UART and pushes state to the browser via WebSocket (Alpine
 ```bash
 go run . -port /dev/ttyUSB0 serve
 go run . -port /dev/ttyUSB0 serve -addr :8080 -interval 2s
+go run . -port /dev/ttyUSB0 serve -api-addr :8081 -accel-interval 16ms
 make gotool-serve PORT=/dev/ttyUSB0
 ```
 
 Open [http://localhost:8080](http://localhost:8080) — shows master firmware info and the ESP-NOW client table from `CLIENT_INFO`.
 
+### External API (second HTTP server)
+
+`serve` starts a separate listener (default **`:8081`**, disable with `-api-addr ""`) for external programs. It shares the same UART connection as the dashboard.
+
+| Endpoint | Description |
+|----------|-------------|
+| `GET /` or `GET /api/v1/` | JSON service info (`default_interval_ms`, min/max, `serial_port`) |
+| `WebSocket /ws` | Per-connection accel receive + interval; slave ESP-NOW stream control |
+
+Two layers:
+
+1. **`set_stream`** — this WebSocket connection: whether to receive `accel` JSON and at what poll rate (1 ms … 10 s per client; server UART poll uses the minimum among active subscribers).
+2. **`set_accel_stream`** — firmware: whether a slave sends accel to the master over ESP-NOW (16 ms on the pod).
+
+Polling runs only when at least one connection has `receive_accel: true` **and** at least one slave streams (via `set_accel_stream` or dashboard `:8080`).
+
+**Hello** (on connect; accel is off until `set_stream`):
+
+```json
+{"type":"hello","serial_port":"/dev/ttyUSB0","interval_ms":16,"commands":["set_stream","get_stream","set_accel_stream","get_accel_stream"]}
+```
+
+**Receive accel on this connection** (optional `interval_ms`, default from `-accel-interval`):
+
+```json
+{"type":"set_stream","enable":true,"interval_ms":32}
+{"type":"get_stream"}
+```
+
+Reply:
+
+```json
+{"type":"stream_status","receive_accel":true,"interval_ms":32,"success":true}
+```
+
+**Slave ESP-NOW stream** (per `client_id`):
+
+```json
+{"type":"set_accel_stream","client_id":16,"enable":true}
+{"type":"get_accel_stream","client_id":16}
+```
+
+Reply:
+
+```json
+{"type":"accel_stream_status","client_id":16,"enabled":true,"success":true}
+```
+
+**Accel** (only to connections with `receive_accel: true`, and only while slaves stream):
+
+```json
+{"type":"accel","t":1716900123456789012,"success":true,"clients":[{"client_id":16,"valid":true,"x":12,"y":-34,"z":16384,"age_ms":8}]}
+```
+
+`t` is Unix time in nanoseconds. Each `clients[]` entry is one slave's latest cached sample (raw LSB, ±2g).
+
+Example (Python):
+
+```python
+import asyncio, json, websockets
+
+async def main():
+    async with websockets.connect("ws://127.0.0.1:8081/ws") as ws:
+        print(await ws.recv())  # hello
+        await ws.send(json.dumps({"type": "set_stream", "enable": True, "interval_ms": 16}))
+        print(await ws.recv())  # stream_status
+        await ws.send(json.dumps({"type": "set_accel_stream", "client_id": 16, "enable": True}))
+        print(await ws.recv())  # accel_stream_status
+        while True:
+            msg = json.loads(await ws.recv())
+            if msg.get("type") != "accel" or not msg.get("success"):
+                continue
+            for c in msg.get("clients", []):
+                if c.get("valid"):
+                    print(c["client_id"], c["x"], c["y"], c["z"])
+
+asyncio.run(main())
+```
+
 If the UART device is unplugged or the port disappears, `serve` keeps running and retries on each poll interval; the UI shows **UART off** until the port is available again.
 
 The dashboard can configure nodes using the same UART commands as the CLI:
@@ -78,7 +158,21 @@ The dashboard can configure nodes using the same UART commands as the CLI:
 | Alle Slaves | per-slave ESP-NOW (Master bleibt unverändert; CLI `-all` setzt auch den Master) |
 | Unicast test | `unicast-test -client ID` |
 
-HTTP API (used by the web UI): `GET/POST /api/deadzone`, `POST /api/unicast-test`, `POST /api/find-me`, `POST /api/restart`, `POST /api/ota` (multipart field `firmware`, max 2 MiB).
+HTTP API (used by the web UI): `GET/POST /api/deadzone`, `GET/PUT /api/clients/{id}/accel-stream`, `POST /api/accel-stream` (legacy / `all_clients`), `POST /api/unicast-test`, `POST /api/find-me`, `POST /api/restart`, `POST /api/ota` (multipart field `firmware`, max 2 MiB).
+
+**Accel stream per slave** (must be enabled before values appear; goTool polls only while at least one slave has stream on):
+
+```http
+GET /api/clients/16/accel-stream
+→ {"enabled":false,"client_id":16,"success":true}
+
+PUT /api/clients/16/accel-stream
+Content-Type: application/json
+{"enable": true}
+→ {"enabled":true,"client_id":16,"success":true}
+```
+
+Enable all slaves: `POST /api/accel-stream` with `{"write":true,"enable":true,"all_clients":true}`.
 
 | UI / API | Behaviour |
 |----------|-----------|

goTool/accel_stream_ctl.go

@@ -0,0 +1,40 @@
+package main
+
+import "sync"
+
+// accelStreamCtl tracks which slaves the host wants to poll for accel (mirrors firmware).
+type accelStreamCtl struct {
+	mu      sync.Mutex
+	enabled map[uint32]struct{}
+}
+
+func newAccelStreamCtl() *accelStreamCtl {
+	return &accelStreamCtl{enabled: make(map[uint32]struct{})}
+}
+
+func (c *accelStreamCtl) Set(clientID uint32, on bool) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if on {
+		c.enabled[clientID] = struct{}{}
+	} else {
+		delete(c.enabled, clientID)
+	}
+}
+
+func (c *accelStreamCtl) Any() bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return len(c.enabled) > 0
+}
+
+func (c *accelStreamCtl) SyncFromClients(clients []ClientView) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.enabled = make(map[uint32]struct{})
+	for _, cl := range clients {
+		if cl.AccelStream {
+			c.enabled[cl.ID] = struct{}{}
+		}
+	}
+}

goTool/api_accel_stream.go

@@ -0,0 +1,220 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strconv"
+
+	"powerpod/gotool/pb"
+)
+
+type accelStreamAPIRequest struct {
+	Write      bool   `json:"write"`
+	Enable     bool   `json:"enable"`
+	ClientID   uint32 `json:"client_id"`
+	AllClients bool   `json:"all_clients"`
+}
+
+type accelStreamAPIResponse struct {
+	Enabled       bool   `json:"enabled"`
+	ClientID      uint32 `json:"client_id"`
+	Success       bool   `json:"success"`
+	SlavesUpdated uint32 `json:"slaves_updated"`
+	Error         string `json:"error,omitempty"`
+}
+
+type clientAccelStreamBody struct {
+	Enable bool `json:"enable"`
+}
+
+func mountAccelStreamAPI(mux *http.ServeMux, link *managedSerial, hub *wsHub, ctl *accelStreamCtl) {
+	mux.HandleFunc("GET /api/clients/{clientID}/accel-stream", func(w http.ResponseWriter, r *http.Request) {
+		clientID, err := parsePathClientID(r)
+		if err != nil {
+			writeJSON(w, http.StatusBadRequest, accelStreamAPIResponse{Error: err.Error()})
+			return
+		}
+		serveAccelStreamGet(w, clientID, link, hub, ctl)
+	})
+	mux.HandleFunc("PUT /api/clients/{clientID}/accel-stream", func(w http.ResponseWriter, r *http.Request) {
+		clientID, err := parsePathClientID(r)
+		if err != nil {
+			writeJSON(w, http.StatusBadRequest, accelStreamAPIResponse{Error: err.Error()})
+			return
+		}
+		serveClientAccelStreamPut(w, r, clientID, link, hub, ctl)
+	})
+
+	mux.HandleFunc("/api/accel-stream", func(w http.ResponseWriter, r *http.Request) {
+		switch r.Method {
+		case http.MethodGet:
+			serveAccelStreamGetQuery(w, r, link, hub, ctl)
+		case http.MethodPost:
+			serveAccelStreamPost(w, r, link, hub, ctl)
+		default:
+			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		}
+	})
+}
+
+func parsePathClientID(r *http.Request) (uint32, error) {
+	s := r.PathValue("clientID")
+	if s == "" {
+		return 0, fmt.Errorf("client_id required")
+	}
+	v, err := strconv.ParseUint(s, 10, 32)
+	if err != nil || v == 0 {
+		return 0, fmt.Errorf("invalid client_id")
+	}
+	return uint32(v), nil
+}
+
+func applyAccelStreamClient(link *managedSerial, hub *wsHub, ctl *accelStreamCtl, clientID uint32, enable bool) accelStreamAPIResponse {
+	resp, err := link.AccelStream(&pb.AccelStreamRequest{
+		Write:    true,
+		Enable:   enable,
+		ClientId: clientID,
+	})
+	if err != nil {
+		return accelStreamAPIResponse{
+			ClientID: clientID,
+			Error:    err.Error(),
+		}
+	}
+	out := accelStreamAPIResponse{
+		Enabled:       enable,
+		ClientID:      resp.GetClientId(),
+		Success:       resp.GetSuccess(),
+		SlavesUpdated: resp.GetSlavesUpdated(),
+	}
+	if resp.GetSuccess() {
+		if ctl != nil {
+			ctl.Set(clientID, enable)
+		}
+		if hub != nil {
+			hub.patchClientAccelStream(clientID, enable)
+		}
+	} else {
+		out.Enabled = resp.GetEnabled()
+	}
+	return out
+}
+
+func serveAccelStreamGet(w http.ResponseWriter, clientID uint32, link *managedSerial, hub *wsHub, ctl *accelStreamCtl) {
+	resp, err := link.AccelStreamPoll(&pb.AccelStreamRequest{
+		Write:    false,
+		ClientId: clientID,
+	})
+	if err != nil {
+		writeJSON(w, http.StatusServiceUnavailable, accelStreamAPIResponse{
+			ClientID: clientID,
+			Error:    err.Error(),
+		})
+		return
+	}
+	if ctl != nil {
+		ctl.Set(clientID, resp.GetEnabled())
+	}
+	writeJSON(w, http.StatusOK, accelStreamAPIResponse{
+		Enabled:  resp.GetEnabled(),
+		ClientID: resp.GetClientId(),
+		Success:  resp.GetSuccess(),
+	})
+}
+
+func serveAccelStreamGetQuery(w http.ResponseWriter, r *http.Request, link *managedSerial, hub *wsHub, ctl *accelStreamCtl) {
+	clientID, err := parseUintQuery(r, "client_id", 0)
+	if err != nil || clientID == 0 {
+		writeJSON(w, http.StatusBadRequest, accelStreamAPIResponse{Error: "client_id required"})
+		return
+	}
+	serveAccelStreamGet(w, clientID, link, hub, ctl)
+}
+
+func serveClientAccelStreamPut(w http.ResponseWriter, r *http.Request, clientID uint32, link *managedSerial, hub *wsHub, ctl *accelStreamCtl) {
+	var body clientAccelStreamBody
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+		writeJSON(w, http.StatusBadRequest, accelStreamAPIResponse{Error: "invalid JSON"})
+		return
+	}
+	out := applyAccelStreamClient(link, hub, ctl, clientID, body.Enable)
+	status := http.StatusOK
+	if out.Error != "" {
+		status = http.StatusServiceUnavailable
+	} else if !out.Success {
+		status = http.StatusServiceUnavailable
+	}
+	writeJSON(w, status, out)
+}
+
+func serveAccelStreamPost(w http.ResponseWriter, r *http.Request, link *managedSerial, hub *wsHub, ctl *accelStreamCtl) {
+	var body accelStreamAPIRequest
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+		writeJSON(w, http.StatusBadRequest, accelStreamAPIResponse{Error: "invalid JSON"})
+		return
+	}
+
+	if body.AllClients {
+		updated, err := applyAccelStreamAll(link, body.Enable)
+		if err != nil {
+			writeJSON(w, http.StatusServiceUnavailable, accelStreamAPIResponse{Error: err.Error()})
+			return
+		}
+		clients, _ := link.listClientsPoll()
+		for _, c := range clients {
+			if ctl != nil {
+				ctl.Set(c.GetId(), body.Enable)
+			}
+			if hub != nil {
+				hub.patchClientAccelStream(c.GetId(), body.Enable)
+			}
+		}
+		writeJSON(w, http.StatusOK, accelStreamAPIResponse{
+			Enabled:       body.Enable,
+			Success:       updated > 0,
+			SlavesUpdated: updated,
+		})
+		return
+	}
+
+	if body.ClientID == 0 {
+		writeJSON(w, http.StatusBadRequest, accelStreamAPIResponse{Error: "client_id required"})
+		return
+	}
+
+	out := applyAccelStreamClient(link, hub, ctl, body.ClientID, body.Enable)
+	status := http.StatusOK
+	if out.Error != "" || !out.Success {
+		status = http.StatusServiceUnavailable
+	}
+	writeJSON(w, status, out)
+}
+
+func applyAccelStreamAll(link *managedSerial, enable bool) (uint32, error) {
+	clients, err := link.listClients()
+	if err != nil {
+		return 0, err
+	}
+	var updated uint32
+	for _, c := range clients {
+		resp, err := link.AccelStream(&pb.AccelStreamRequest{
+			Write:    true,
+			Enable:   enable,
+			ClientId: c.GetId(),
+		})
+		if err != nil {
+			continue
+		}
+		if resp.GetSuccess() {
+			updated++
+		}
+	}
+	if len(clients) == 0 {
+		return 0, fmt.Errorf("no slaves registered")
+	}
+	if updated == 0 {
+		return 0, fmt.Errorf("accel stream not applied to any slave")
+	}
+	return updated, nil
+}

goTool/api_serve.go

@@ -67,7 +67,8 @@ type otaAPIResponse struct {
 	Error         string `json:"error,omitempty"`
 }
 
-func mountServeAPI(mux *http.ServeMux, link *managedSerial, hub *wsHub) {
+func mountServeAPI(mux *http.ServeMux, link *managedSerial, hub *wsHub, streamCtl *accelStreamCtl) {
+	mountAccelStreamAPI(mux, link, hub, streamCtl)
 	mux.HandleFunc("/api/deadzone", func(w http.ResponseWriter, r *http.Request) {
 		switch r.Method {
 		case http.MethodGet:

goTool/api_stream.go

@@ -0,0 +1,476 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"log"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/gorilla/websocket"
+	"powerpod/gotool/pb"
+)
+
+const (
+	defaultAccelStreamInterval = 16 * time.Millisecond
+	minAPIStreamInterval       = 1 * time.Millisecond
+	maxAPIStreamInterval       = 10 * time.Second
+)
+
+// AccelClientSample is one slave's cached accel on the master.
+type AccelClientSample struct {
+	ClientID uint32 `json:"client_id"`
+	Valid    bool   `json:"valid"`
+	X        int32  `json:"x,omitempty"`
+	Y        int32  `json:"y,omitempty"`
+	Z        int32  `json:"z,omitempty"`
+	AgeMs    uint32 `json:"age_ms,omitempty"`
+}
+
+// AccelStreamMessage is sent to external WebSocket clients.
+type AccelStreamMessage struct {
+	Type       string   `json:"type"` // "hello" | "accel"
+	Serial     string   `json:"serial_port,omitempty"`
+	IntervalMs int      `json:"interval_ms,omitempty"`
+	Commands   []string `json:"commands,omitempty"`
+
+	T       int64               `json:"t,omitempty"` // Unix nanoseconds
+	Success bool                `json:"success,omitempty"`
+	Clients []AccelClientSample `json:"clients,omitempty"`
+	Error   string              `json:"error,omitempty"`
+}
+
+// StreamStatusMessage is the reply to set_stream / get_stream (this connection).
+type StreamStatusMessage struct {
+	Type         string `json:"type"` // "stream_status"
+	ReceiveAccel bool   `json:"receive_accel"`
+	IntervalMs   int    `json:"interval_ms"`
+	Success      bool   `json:"success"`
+	Error        string `json:"error,omitempty"`
+}
+
+// AccelStreamStatusMessage is the reply to set_accel_stream / get_accel_stream (slave).
+type AccelStreamStatusMessage struct {
+	Type          string `json:"type"` // "accel_stream_status"
+	ClientID      uint32 `json:"client_id"`
+	Enabled       bool   `json:"enabled"`
+	Success       bool   `json:"success"`
+	SlavesUpdated uint32 `json:"slaves_updated,omitempty"`
+	Error         string `json:"error,omitempty"`
+}
+
+type accelWSCommand struct {
+	Type       string `json:"type"`
+	ClientID   uint32 `json:"client_id"`
+	Enable     *bool  `json:"enable"`
+	IntervalMs *int   `json:"interval_ms"`
+}
+
+type APIInfoResponse struct {
+	Name             string `json:"name"`
+	Version          string `json:"version"`
+	SerialPort       string `json:"serial_port"`
+	WebSocket        string `json:"websocket"`
+	DefaultIntervalMs int    `json:"default_interval_ms"`
+	MinIntervalMs    int    `json:"min_interval_ms"`
+	MaxIntervalMs    int    `json:"max_interval_ms"`
+	Description      string `json:"description"`
+}
+
+type wsSubscriber struct {
+	conn         *websocket.Conn
+	receiveAccel bool
+	interval     time.Duration
+	lastSent     time.Time
+}
+
+type accelStreamHub struct {
+	mu            sync.RWMutex
+	clients       map[*websocket.Conn]*wsSubscriber
+	defaultInterval time.Duration
+	configChanged chan struct{}
+}
+
+func newAccelStreamHub(defaultInterval time.Duration) *accelStreamHub {
+	return &accelStreamHub{
+		clients:         make(map[*websocket.Conn]*wsSubscriber),
+		defaultInterval: defaultInterval,
+		configChanged:   make(chan struct{}, 1),
+	}
+}
+
+func (h *accelStreamHub) notifyConfigChanged() {
+	select {
+	case h.configChanged <- struct{}{}:
+	default:
+	}
+}
+
+func clampAPIInterval(d time.Duration) time.Duration {
+	if d < minAPIStreamInterval {
+		return minAPIStreamInterval
+	}
+	if d > maxAPIStreamInterval {
+		return maxAPIStreamInterval
+	}
+	return d
+}
+
+func (h *accelStreamHub) register(conn *websocket.Conn, portName string) *wsSubscriber {
+	sub := &wsSubscriber{
+		conn:         conn,
+		receiveAccel: false,
+		interval:     h.defaultInterval,
+	}
+	h.mu.Lock()
+	h.clients[conn] = sub
+	h.mu.Unlock()
+
+	hello := AccelStreamMessage{
+		Type:       "hello",
+		Serial:     portName,
+		IntervalMs: int(h.defaultInterval / time.Millisecond),
+		Commands:   []string{"set_stream", "get_stream", "set_accel_stream", "get_accel_stream"},
+	}
+	if data, err := json.Marshal(hello); err == nil {
+		_ = conn.WriteMessage(websocket.TextMessage, data)
+	}
+	return sub
+}
+
+func (h *accelStreamHub) unregister(conn *websocket.Conn) {
+	h.mu.Lock()
+	delete(h.clients, conn)
+	h.mu.Unlock()
+	h.notifyConfigChanged()
+}
+
+func (h *accelStreamHub) anyWantsAccel() bool {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	for _, sub := range h.clients {
+		if sub.receiveAccel {
+			return true
+		}
+	}
+	return false
+}
+
+func (h *accelStreamHub) minWantedInterval() time.Duration {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	var min time.Duration
+	for _, sub := range h.clients {
+		if !sub.receiveAccel {
+			continue
+		}
+		if min == 0 || sub.interval < min {
+			min = sub.interval
+		}
+	}
+	if min == 0 {
+		return h.defaultInterval
+	}
+	return min
+}
+
+func (h *accelStreamHub) setStream(sub *wsSubscriber, enable bool, intervalMs *int) StreamStatusMessage {
+	h.mu.Lock()
+	sub.receiveAccel = enable
+	if intervalMs != nil {
+		sub.interval = clampAPIInterval(time.Duration(*intervalMs) * time.Millisecond)
+	}
+	ms := int(sub.interval / time.Millisecond)
+	h.mu.Unlock()
+	h.notifyConfigChanged()
+
+	return StreamStatusMessage{
+		Type:         "stream_status",
+		ReceiveAccel: enable,
+		IntervalMs:   ms,
+		Success:      true,
+	}
+}
+
+func (h *accelStreamHub) getStream(sub *wsSubscriber) StreamStatusMessage {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	return StreamStatusMessage{
+		Type:         "stream_status",
+		ReceiveAccel: sub.receiveAccel,
+		IntervalMs:   int(sub.interval / time.Millisecond),
+		Success:      true,
+	}
+}
+
+func (h *accelStreamHub) deliver(msg AccelStreamMessage) {
+	data, err := json.Marshal(msg)
+	if err != nil {
+		return
+	}
+
+	now := time.Now()
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	for conn, sub := range h.clients {
+		if !sub.receiveAccel {
+			continue
+		}
+		if !sub.lastSent.IsZero() && now.Sub(sub.lastSent) < sub.interval {
+			continue
+		}
+		sub.lastSent = now
+		if err := conn.WriteMessage(websocket.TextMessage, data); err != nil {
+			delete(h.clients, conn)
+			_ = conn.Close()
+		}
+	}
+}
+
+func runAccelStreamer(link *managedSerial, hub *accelStreamHub, dash *wsHub, ctl *accelStreamCtl, stop <-chan struct{}) {
+	var ticker *time.Ticker
+	var tick <-chan time.Time
+
+	resetTicker := func() {
+		if ticker != nil {
+			ticker.Stop()
+		}
+		interval := hub.minWantedInterval()
+		ticker = time.NewTicker(interval)
+		tick = ticker.C
+	}
+	resetTicker()
+	defer func() {
+		if ticker != nil {
+			ticker.Stop()
+		}
+	}()
+
+	for {
+		select {
+		case <-stop:
+			return
+		case <-hub.configChanged:
+			resetTicker()
+		case <-tick:
+			if !hub.anyWantsAccel() {
+				continue
+			}
+			if !accelStreamPollingActive(dash, ctl) {
+				continue
+			}
+			now := time.Now().UnixNano()
+			resp, err := link.readAccelSnapshotPoll(0)
+			if errors.Is(err, errUARTBusy) {
+				hub.deliver(AccelStreamMessage{
+					Type:    "accel",
+					T:       now,
+					Success: false,
+					Error:   "uart busy",
+				})
+				continue
+			}
+			if err != nil {
+				hub.deliver(AccelStreamMessage{
+					Type:    "accel",
+					T:       now,
+					Success: false,
+					Error:   err.Error(),
+				})
+				continue
+			}
+			clients := make([]AccelClientSample, 0, len(resp.GetSamples()))
+			for _, s := range resp.GetSamples() {
+				clients = append(clients, AccelClientSample{
+					ClientID: s.GetClientId(),
+					Valid:    s.GetValid(),
+					X:        s.GetX(),
+					Y:        s.GetY(),
+					Z:        s.GetZ(),
+					AgeMs:    s.GetAgeMs(),
+				})
+			}
+			hub.deliver(AccelStreamMessage{
+				Type:    "accel",
+				T:       now,
+				Success: true,
+				Clients: clients,
+			})
+		}
+	}
+}
+
+func accelStreamPollingActive(dash *wsHub, ctl *accelStreamCtl) bool {
+	if ctl != nil && ctl.Any() {
+		return true
+	}
+	return dash != nil && dash.anyAccelStreamEnabled()
+}
+
+func writeStreamStatus(conn *websocket.Conn, msg StreamStatusMessage) {
+	data, err := json.Marshal(msg)
+	if err != nil {
+		return
+	}
+	_ = conn.WriteMessage(websocket.TextMessage, data)
+}
+
+func writeAccelStreamStatus(conn *websocket.Conn, out accelStreamAPIResponse) {
+	msg := AccelStreamStatusMessage{
+		Type:          "accel_stream_status",
+		ClientID:      out.ClientID,
+		Enabled:       out.Enabled,
+		Success:       out.Success,
+		SlavesUpdated: out.SlavesUpdated,
+		Error:         out.Error,
+	}
+	data, err := json.Marshal(msg)
+	if err != nil {
+		return
+	}
+	_ = conn.WriteMessage(websocket.TextMessage, data)
+}
+
+func handleAccelWSCommand(conn *websocket.Conn, sub *wsSubscriber, data []byte, link *managedSerial, dash *wsHub, ctl *accelStreamCtl, hub *accelStreamHub) {
+	var cmd accelWSCommand
+	if err := json.Unmarshal(data, &cmd); err != nil {
+		writeStreamStatus(conn, StreamStatusMessage{Type: "stream_status", Error: "invalid JSON"})
+		return
+	}
+
+	switch cmd.Type {
+	case "set_stream":
+		if cmd.Enable == nil {
+			writeStreamStatus(conn, StreamStatusMessage{
+				Type:  "stream_status",
+				Error: "enable required",
+			})
+			return
+		}
+		writeStreamStatus(conn, hub.setStream(sub, *cmd.Enable, cmd.IntervalMs))
+
+	case "get_stream":
+		writeStreamStatus(conn, hub.getStream(sub))
+
+	case "set_accel_stream":
+		if cmd.ClientID == 0 {
+			writeAccelStreamStatus(conn, accelStreamAPIResponse{Error: "client_id required"})
+			return
+		}
+		if cmd.Enable == nil {
+			writeAccelStreamStatus(conn, accelStreamAPIResponse{
+				ClientID: cmd.ClientID,
+				Error:    "enable required",
+			})
+			return
+		}
+		writeAccelStreamStatus(conn, applyAccelStreamClient(link, dash, ctl, cmd.ClientID, *cmd.Enable))
+
+	case "get_accel_stream":
+		if cmd.ClientID == 0 {
+			writeAccelStreamStatus(conn, accelStreamAPIResponse{Error: "client_id required"})
+			return
+		}
+		resp, err := link.AccelStreamPoll(&pb.AccelStreamRequest{
+			Write:    false,
+			ClientId: cmd.ClientID,
+		})
+		if err != nil {
+			writeAccelStreamStatus(conn, accelStreamAPIResponse{
+				ClientID: cmd.ClientID,
+				Error:    err.Error(),
+			})
+			return
+		}
+		if ctl != nil {
+			ctl.Set(cmd.ClientID, resp.GetEnabled())
+		}
+		writeAccelStreamStatus(conn, accelStreamAPIResponse{
+			Enabled:  resp.GetEnabled(),
+			ClientID: resp.GetClientId(),
+			Success:  resp.GetSuccess(),
+		})
+
+	default:
+		writeStreamStatus(conn, StreamStatusMessage{
+			Type:  "stream_status",
+			Error: "unknown type (set_stream, get_stream, set_accel_stream, get_accel_stream)",
+		})
+	}
+}
+
+func serveExternalWS(conn *websocket.Conn, link *managedSerial, dash *wsHub, ctl *accelStreamCtl, portName string, hub *accelStreamHub) {
+	sub := hub.register(conn, portName)
+	defer hub.unregister(conn)
+	defer conn.Close()
+
+	for {
+		_, data, err := conn.ReadMessage()
+		if err != nil {
+			return
+		}
+		handleAccelWSCommand(conn, sub, data, link, dash, ctl, hub)
+	}
+}
+
+func mountExternalAPI(mux *http.ServeMux, portName string, defaultInterval time.Duration, hub *accelStreamHub, link *managedSerial, dash *wsHub, ctl *accelStreamCtl) {
+	defMs := int(defaultInterval / time.Millisecond)
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/" && r.URL.Path != "/api/v1" && r.URL.Path != "/api/v1/" {
+			http.NotFound(w, r)
+			return
+		}
+		if r.Method != http.MethodGet {
+			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+			return
+		}
+		writeJSON(w, http.StatusOK, APIInfoResponse{
+			Name:              "powerpod-external-api",
+			Version:           "1",
+			SerialPort:        portName,
+			WebSocket:         "/ws",
+			DefaultIntervalMs: defMs,
+			MinIntervalMs:     int(minAPIStreamInterval / time.Millisecond),
+			MaxIntervalMs:     int(maxAPIStreamInterval / time.Millisecond),
+			Description:       "WebSocket: per-connection accel receive + interval; slave stream via set_accel_stream",
+		})
+	})
+
+	mux.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
+		conn, err := wsUpgrader.Upgrade(w, r, nil)
+		if err != nil {
+			log.Printf("api websocket upgrade: %v", err)
+			return
+		}
+		serveExternalWS(conn, link, dash, ctl, portName, hub)
+	})
+}
+
+func runAPIServer(portName string, link *managedSerial, addr string, defaultInterval time.Duration, dash *wsHub, ctl *accelStreamCtl, stop <-chan struct{}) *http.Server {
+	hub := newAccelStreamHub(defaultInterval)
+	go runAccelStreamer(link, hub, dash, ctl, stop)
+
+	mux := http.NewServeMux()
+	mountExternalAPI(mux, portName, defaultInterval, hub, link, dash, ctl)
+
+	srv := &http.Server{Addr: addr, Handler: mux}
+	go func() {
+		log.Printf("external API http://localhost%s  WebSocket ws://localhost%s/ws  (default accel interval %s, per-client via set_stream)",
+			addr, addr, defaultInterval.String())
+		if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+			log.Printf("external API server: %v", err)
+		}
+	}()
+	return srv
+}
+
+func shutdownAPIServer(srv *http.Server) {
+	if srv == nil {
+		return
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+	_ = srv.Shutdown(ctx)
+}

goTool/client_api.go

@@ -40,6 +40,70 @@ func (m *managedSerial) listClientsPoll() ([]*pb.ClientInfo, error) {
 	return decodeClientsPayload(payload)
 }
 
+func (m *managedSerial) readAccelSnapshotPoll(clientID uint32) (*pb.AccelSnapshotResponse, error) {
+	msg := &pb.UartMessage{
+		Type: pb.MessageType_ACCEL_SNAPSHOT,
+		Payload: &pb.UartMessage_AccelSnapshotRequest{
+			AccelSnapshotRequest: &pb.AccelSnapshotRequest{ClientId: clientID},
+		},
+	}
+	body, err := proto.Marshal(msg)
+	if err != nil {
+		return nil, fmt.Errorf("encode: %w", err)
+	}
+	payload := append([]byte{byte(pb.MessageType_ACCEL_SNAPSHOT)}, body...)
+	respPayload, err := m.exchangePayloadPoll(payload, "ACCEL_SNAPSHOT")
+	if err != nil {
+		return nil, err
+	}
+	return decodeAccelSnapshotPayload(respPayload)
+}
+
+func (m *managedSerial) AccelStream(req *pb.AccelStreamRequest) (*pb.AccelStreamResponse, error) {
+	return m.accelStreamVia(m.withPort, req)
+}
+
+func (m *managedSerial) AccelStreamPoll(req *pb.AccelStreamRequest) (*pb.AccelStreamResponse, error) {
+	return m.accelStreamVia(m.withPortPoll, req)
+}
+
+// SetAccelStream enables or disables the ESP-NOW accel stream for one slave (master UART).
+func (m *managedSerial) SetAccelStream(clientID uint32, enable bool) (*pb.AccelStreamResponse, error) {
+	return m.AccelStream(&pb.AccelStreamRequest{
+		Write:    true,
+		Enable:   enable,
+		ClientId: clientID,
+	})
+}
+
+// GetAccelStream returns whether the accel stream is enabled for a slave on the master.
+func (m *managedSerial) GetAccelStream(clientID uint32) (bool, error) {
+	resp, err := m.AccelStreamPoll(&pb.AccelStreamRequest{
+		Write:    false,
+		ClientId: clientID,
+	})
+	if err != nil {
+		return false, err
+	}
+	if !resp.GetSuccess() {
+		return false, fmt.Errorf("accel stream read failed for client %d", clientID)
+	}
+	return resp.GetEnabled(), nil
+}
+
+func (m *managedSerial) accelStreamVia(
+	portFn func(func(*serialPort) error) error,
+	req *pb.AccelStreamRequest,
+) (*pb.AccelStreamResponse, error) {
+	var resp *pb.AccelStreamResponse
+	err := portFn(func(sp *serialPort) error {
+		var e error
+		resp, e = sp.AccelStream(req)
+		return e
+	})
+	return resp, err
+}
+
 func (m *managedSerial) AccelDeadzone(req *pb.AccelDeadzoneRequest) (*pb.AccelDeadzoneResponse, error) {
 	return m.accelDeadzoneVia(m.withPort, req)
 }
@@ -101,25 +165,43 @@ func decodeClientsPayload(payload []byte) ([]*pb.ClientInfo, error) {
 	return info.GetClients(), nil
 }
 
-func (s *serialPort) readAccel() (*pb.AccelReadResponse, error) {
+func decodeAccelSnapshotPayload(payload []byte) (*pb.AccelSnapshotResponse, error) {
-	payload, err := s.exchange(byte(pb.MessageType_ACCEL_READ), "ACCEL_READ")
+	if len(payload) < 1 {
-	if err != nil {
+		return nil, fmt.Errorf("empty response payload")
-		return nil, err
 	}
 	var msg pb.UartMessage
 	if err := proto.Unmarshal(payload[1:], &msg); err != nil {
 		return nil, fmt.Errorf("decode: %w", err)
 	}
-	if msg.GetType() != pb.MessageType_ACCEL_READ {
+	if msg.GetType() != pb.MessageType_ACCEL_SNAPSHOT {
 		return nil, fmt.Errorf("unexpected type %v", msg.GetType())
 	}
-	r := msg.GetAccelReadResponse()
+	r := msg.GetAccelSnapshotResponse()
 	if r == nil {
-		return nil, fmt.Errorf("missing accel_read_response")
+		return nil, fmt.Errorf("missing accel_snapshot_response")
 	}
 	return r, nil
 }
 
+func (s *serialPort) readAccelSnapshot(clientID uint32) (*pb.AccelSnapshotResponse, error) {
+	msg := &pb.UartMessage{
+		Type: pb.MessageType_ACCEL_SNAPSHOT,
+		Payload: &pb.UartMessage_AccelSnapshotRequest{
+			AccelSnapshotRequest: &pb.AccelSnapshotRequest{ClientId: clientID},
+		},
+	}
+	body, err := proto.Marshal(msg)
+	if err != nil {
+		return nil, fmt.Errorf("encode: %w", err)
+	}
+	payload := append([]byte{byte(pb.MessageType_ACCEL_SNAPSHOT)}, body...)
+	respPayload, err := s.exchangePayload(payload, "ACCEL_SNAPSHOT")
+	if err != nil {
+		return nil, err
+	}
+	return decodeAccelSnapshotPayload(respPayload)
+}
+
 func (s *serialPort) getVersion() (*pb.VersionResponse, error) {
 	payload, err := s.exchange(byte(pb.MessageType_VERSION), "VERSION")
 	if err != nil {
@@ -136,6 +218,33 @@ func (s *serialPort) listClients() ([]*pb.ClientInfo, error) {
 	return decodeClientsPayload(payload)
 }
 
+func (s *serialPort) AccelStream(req *pb.AccelStreamRequest) (*pb.AccelStreamResponse, error) {
+	msg := &pb.UartMessage{
+		Type: pb.MessageType_ACCEL_STREAM,
+		Payload: &pb.UartMessage_AccelStreamRequest{
+			AccelStreamRequest: req,
+		},
+	}
+	body, err := proto.Marshal(msg)
+	if err != nil {
+		return nil, fmt.Errorf("encode: %w", err)
+	}
+	payload := append([]byte{byte(pb.MessageType_ACCEL_STREAM)}, body...)
+	respPayload, err := s.exchangePayload(payload, "ACCEL_STREAM")
+	if err != nil {
+		return nil, err
+	}
+	var respMsg pb.UartMessage
+	if err := proto.Unmarshal(respPayload[1:], &respMsg); err != nil {
+		return nil, fmt.Errorf("decode: %w", err)
+	}
+	r := respMsg.GetAccelStreamResponse()
+	if r == nil {
+		return nil, fmt.Errorf("missing accel_stream_response")
+	}
+	return r, nil
+}
+
 func (s *serialPort) accelDeadzone(req *pb.AccelDeadzoneRequest) (*pb.AccelDeadzoneResponse, error) {
 	msg := &pb.UartMessage{
 		Type: pb.MessageType_ACCEL_DEADZONE,
@@ -234,6 +343,28 @@ func (s *serialPort) GetVersion() (*pb.VersionResponse, error) { return s.getVer
 
 func (s *serialPort) ListClients() ([]*pb.ClientInfo, error) { return s.listClients() }
 
+func (s *serialPort) SetAccelStream(clientID uint32, enable bool) (*pb.AccelStreamResponse, error) {
+	return s.AccelStream(&pb.AccelStreamRequest{
+		Write:    true,
+		Enable:   enable,
+		ClientId: clientID,
+	})
+}
+
+func (s *serialPort) GetAccelStream(clientID uint32) (bool, error) {
+	resp, err := s.AccelStream(&pb.AccelStreamRequest{
+		Write:    false,
+		ClientId: clientID,
+	})
+	if err != nil {
+		return false, err
+	}
+	if !resp.GetSuccess() {
+		return false, fmt.Errorf("accel stream read failed for client %d", clientID)
+	}
+	return resp.GetEnabled(), nil
+}
+
 func (s *serialPort) AccelDeadzone(req *pb.AccelDeadzoneRequest) (*pb.AccelDeadzoneResponse, error) {
 	return s.accelDeadzone(req)
 }

goTool/cmd_accel.go

@@ -5,13 +5,26 @@ import (
 )
 
 func runAccel(sp *serialPort) error {
-	r, err := sp.readAccel()
+	return runAccelSnapshot(sp, 0)
+}
+
+func runAccelSnapshot(sp *serialPort, clientID uint32) error {
+	r, err := sp.readAccelSnapshot(clientID)
 	if err != nil {
 		return err
 	}
-	if !r.GetSuccess() {
+	samples := r.GetSamples()
-		return fmt.Errorf("accel read failed (sensor not ready?)")
+	if len(samples) == 0 {
-	}
+		fmt.Println("no accel samples (no slaves or no ESP-NOW stream yet)")
-	fmt.Printf("accel: x=%d y=%d z=%d (raw LSB, ±2g)\n", r.GetX(), r.GetY(), r.GetZ())
+		return nil
+	}
+	for _, s := range samples {
+		if !s.GetValid() {
+			fmt.Printf("client %d: no sample yet\n", s.GetClientId())
+			continue
+		}
+		fmt.Printf("client %d: x=%d y=%d z=%d (age %d ms, raw LSB ±2g)\n",
+			s.GetClientId(), s.GetX(), s.GetY(), s.GetZ(), s.GetAgeMs())
+	}
 	return nil
 }

goTool/cmd_serve.go

@@ -21,7 +21,9 @@ var wsUpgrader = websocket.Upgrader{
 
 func runServe(portName string, baud int, args []string) error {
 	serveFlags := flag.NewFlagSet("serve", flag.ExitOnError)
-	addr := serveFlags.String("addr", ":8080", "HTTP listen address")
+	addr := serveFlags.String("addr", ":8080", "dashboard HTTP listen address")
+	apiAddr := serveFlags.String("api-addr", ":8081", "external API HTTP listen address (empty to disable)")
+	accelInterval := serveFlags.Duration("accel-interval", defaultAccelStreamInterval, "accel WebSocket sample period on API server")
 	interval := serveFlags.Duration("interval", 2*time.Second, "UART poll interval")
 	if err := serveFlags.Parse(args); err != nil {
 		return err
@@ -35,12 +37,20 @@ func runServe(portName string, baud int, args []string) error {
 	defer link.Close()
 
 	hub := newWSHub()
+	streamCtl := newAccelStreamCtl()
 	stop := make(chan struct{})
 	defer close(stop)
-	go runPoller(link, portName, hub, *interval, stop)
+	go runPoller(link, portName, hub, streamCtl, *interval, stop)
+	go runAccelDashboardPoller(link, hub, *accelInterval, stop)
+
+	var apiSrv *http.Server
+	if *apiAddr != "" {
+		apiSrv = runAPIServer(portName, link, *apiAddr, *accelInterval, hub, streamCtl, stop)
+		defer shutdownAPIServer(apiSrv)
+	}
 
 	mux := http.NewServeMux()
-	mountServeAPI(mux, link, hub)
+	mountServeAPI(mux, link, hub, streamCtl)
 	mux.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
 		conn, err := wsUpgrader.Upgrade(w, r, nil)
 		if err != nil {
@@ -64,7 +74,10 @@ func runServe(portName string, baud int, args []string) error {
 	}
 	mux.Handle("/", http.FileServer(http.FS(ui)))
 
-	log.Printf("dashboard http://localhost%s  (UART %s @ %d baud, poll %s, auto-reconnect)",
+	log.Printf("dashboard http://localhost%s  (UART %s @ %d baud, poll %s, accel %s, auto-reconnect)",
-		*addr, portName, baud, interval.String())
+		*addr, portName, baud, interval.String(), accelInterval.String())
+	if *apiAddr == "" {
+		log.Printf("external API disabled (-api-addr \"\")")
+	}
 	return http.ListenAndServe(*addr, mux)
 }

goTool/dashboard.go

@@ -32,6 +32,12 @@ type ClientView struct {
 	Used            bool   `json:"used"`
 	LastPing        uint32 `json:"last_ping"`
 	LastSuccessPing uint32 `json:"last_success_ping"`
+	AccelValid      bool   `json:"accel_valid"`
+	AccelX          int32  `json:"accel_x"`
+	AccelY          int32  `json:"accel_y"`
+	AccelZ          int32  `json:"accel_z"`
+	AccelAgeMs      uint32 `json:"accel_age_ms"`
+	AccelStream     bool   `json:"accel_stream"`
 }
 
 type DashboardState struct {
@@ -56,6 +62,8 @@ func newWSHub() *wsHub {
 
 func (h *wsHub) setState(st DashboardState) {
 	h.mu.Lock()
+	prev := h.state.Clients
+	st.Clients = preserveClientAccel(st.Clients, prev)
 	h.state = st
 	conns := make([]*websocket.Conn, 0, len(h.clients))
 	for c := range h.clients {
@@ -89,6 +97,136 @@ func (h *wsHub) unregister(c *websocket.Conn) {
 	h.mu.Unlock()
 }
 
+func applyAccelSamples(clients []ClientView, samples []*pb.AccelSample) []ClientView {
+	if len(samples) == 0 {
+		return clients
+	}
+	byID := make(map[uint32]*pb.AccelSample, len(samples))
+	for _, s := range samples {
+		byID[s.GetClientId()] = s
+	}
+	out := make([]ClientView, len(clients))
+	for i, c := range clients {
+		out[i] = c
+		if !c.AccelStream {
+			out[i].AccelValid = false
+			continue
+		}
+		s, ok := byID[c.ID]
+		if !ok {
+			continue
+		}
+		out[i].AccelValid = s.GetValid()
+		if s.GetValid() {
+			out[i].AccelX = s.GetX()
+			out[i].AccelY = s.GetY()
+			out[i].AccelZ = s.GetZ()
+			out[i].AccelAgeMs = s.GetAgeMs()
+		}
+	}
+	return out
+}
+
+func preserveClientAccel(newClients, oldClients []ClientView) []ClientView {
+	if len(oldClients) == 0 {
+		return newClients
+	}
+	oldByID := make(map[uint32]ClientView, len(oldClients))
+	for _, c := range oldClients {
+		oldByID[c.ID] = c
+	}
+	out := make([]ClientView, len(newClients))
+	for i, c := range newClients {
+		out[i] = c
+		if !c.AccelStream {
+			continue
+		}
+		prev, ok := oldByID[c.ID]
+		if !ok || !prev.AccelValid {
+			continue
+		}
+		if !c.AccelValid {
+			out[i].AccelValid = prev.AccelValid
+			out[i].AccelX = prev.AccelX
+			out[i].AccelY = prev.AccelY
+			out[i].AccelZ = prev.AccelZ
+			out[i].AccelAgeMs = prev.AccelAgeMs
+		}
+	}
+	return out
+}
+
+func anyClientAccelStream(clients []ClientView) bool {
+	for _, c := range clients {
+		if c.AccelStream {
+			return true
+		}
+	}
+	return false
+}
+
+// patchClientAccelStream updates stream flag immediately (e.g. after REST) and pushes WS.
+func (h *wsHub) patchClientAccelStream(clientID uint32, enabled bool) {
+	h.mu.Lock()
+	for i := range h.state.Clients {
+		if h.state.Clients[i].ID != clientID {
+			continue
+		}
+		h.state.Clients[i].AccelStream = enabled
+		if !enabled {
+			h.state.Clients[i].AccelValid = false
+			h.state.Clients[i].AccelX = 0
+			h.state.Clients[i].AccelY = 0
+			h.state.Clients[i].AccelZ = 0
+			h.state.Clients[i].AccelAgeMs = 0
+		}
+		break
+	}
+	st := h.state
+	st.UpdatedAt = time.Now().Format(time.RFC3339)
+	conns := make([]*websocket.Conn, 0, len(h.clients))
+	for c := range h.clients {
+		conns = append(conns, c)
+	}
+	h.mu.Unlock()
+
+	data, err := json.Marshal(st)
+	if err != nil {
+		return
+	}
+	for _, c := range conns {
+		_ = c.WriteMessage(websocket.TextMessage, data)
+	}
+}
+
+func (h *wsHub) anyAccelStreamEnabled() bool {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	return anyClientAccelStream(h.state.Clients)
+}
+
+// mergeAccel updates cached accel on clients and pushes state to dashboard WebSockets.
+func (h *wsHub) mergeAccel(samples []*pb.AccelSample) {
+	h.mu.Lock()
+	st := h.state
+	st.Clients = applyAccelSamples(st.Clients, samples)
+	st.UpdatedAt = time.Now().Format(time.RFC3339)
+	h.state = st
+	conns := make([]*websocket.Conn, 0, len(h.clients))
+	for c := range h.clients {
+		conns = append(conns, c)
+	}
+	h.mu.Unlock()
+
+	data, err := json.Marshal(st)
+	if err != nil {
+		return
+	}
+	for _, c := range conns {
+		_ = c.WriteMessage(websocket.TextMessage, data)
+	}
+}
+
 func (h *wsHub) broadcastRaw(v any) {
 	h.mu.RLock()
 	conns := make([]*websocket.Conn, 0, len(h.clients))
@@ -106,7 +244,7 @@ func (h *wsHub) broadcastRaw(v any) {
 	}
 }
 
-func pollDashboard(link *managedSerial, portName string, last *DashboardState) DashboardState {
+func pollDashboard(link *managedSerial, portName string, last *DashboardState, streamCtl *accelStreamCtl) DashboardState {
 	st := DashboardState{
 		UpdatedAt:  time.Now().Format(time.RFC3339),
 		SerialPort: portName,
@@ -152,15 +290,63 @@ func pollDashboard(link *managedSerial, portName string, last *DashboardState) D
 			Used:            c.GetUsed(),
 			LastPing:        c.GetLastPing(),
 			LastSuccessPing: c.GetLastSuccessPing(),
-		}
+			AccelStream:     c.GetAccelStreamEnabled(),
-		if dz, err := readDeadzonePoll(link, c.GetId()); err == nil {
-			cv.Deadzone = dz
 		}
 		st.Clients = append(st.Clients, cv)
 	}
+	if anyClientAccelStream(st.Clients) {
+		for i := range st.Clients {
+			if !st.Clients[i].AccelStream {
+				continue
+			}
+			if dz, err := readDeadzonePoll(link, st.Clients[i].ID); err == nil {
+				st.Clients[i].Deadzone = dz
+			}
+		}
+		if snap, err := link.readAccelSnapshotPoll(0); err == nil {
+			st.Clients = applyAccelSamples(st.Clients, snap.GetSamples())
+		}
+	} else {
+		for i, c := range clients {
+			if dz, err := readDeadzonePoll(link, c.GetId()); err == nil {
+				st.Clients[i].Deadzone = dz
+			}
+		}
+	}
+	if streamCtl != nil {
+		streamCtl.SyncFromClients(st.Clients)
+	}
 	return st
 }
 
+func runAccelDashboardPoller(link *managedSerial, hub *wsHub, interval time.Duration, stop <-chan struct{}) {
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-stop:
+			return
+		case <-ticker.C:
+			if hub.clientCount() == 0 || !hub.anyAccelStreamEnabled() {
+				continue
+			}
+			snap, err := link.readAccelSnapshotPoll(0)
+			if err != nil {
+				continue
+			}
+			hub.mergeAccel(snap.GetSamples())
+		}
+	}
+}
+
+func (h *wsHub) clientCount() int {
+	h.mu.RLock()
+	n := len(h.clients)
+	h.mu.RUnlock()
+	return n
+}
+
 func pausedPollState(portName string, last *DashboardState) DashboardState {
 	if last != nil && last.UARTConnected {
 		st := *last
@@ -208,14 +394,15 @@ func formatMAC(mac []byte) string {
 	return hex.EncodeToString(mac)
 }
 
-func runPoller(link *managedSerial, portName string, hub *wsHub, interval time.Duration, stop <-chan struct{}) {
+func runPoller(link *managedSerial, portName string, hub *wsHub, streamCtl *accelStreamCtl, interval time.Duration, stop <-chan struct{}) {
+	// streamCtl kept for external API; dashboard uses hub.state AccelStream flags.
 	ticker := time.NewTicker(interval)
 	defer ticker.Stop()
 
 	uartUp := false
 	var lastGood DashboardState
 	publish := func() {
-		st := pollDashboard(link, portName, &lastGood)
+		st := pollDashboard(link, portName, &lastGood, streamCtl)
 		if st.UARTConnected && st.SerialOK {
 			lastGood = st
 		}

goTool/main.go

@@ -16,7 +16,7 @@ func usage() {
 	fmt.Fprintf(os.Stderr, "  version   firmware version and git hash\n")
 	fmt.Fprintf(os.Stderr, "  clients   registered ESP-NOW slaves on the master\n")
 	fmt.Fprintf(os.Stderr, "  deadzone      get/set accelerometer deadzone (LSB)\n")
-	fmt.Fprintf(os.Stderr, "  accel         read current accelerometer XYZ (raw LSB)\n")
+	fmt.Fprintf(os.Stderr, "  accel         read cached slave accel snapshot from master\n")
 	fmt.Fprintf(os.Stderr, "  unicast-test  send ESP-NOW unicast test to one slave\n")
 	fmt.Fprintf(os.Stderr, "  test          run automated scenario (see testdata/)\n")
 	fmt.Fprintf(os.Stderr, "  serve         web dashboard (Bootstrap + WebSocket)\n")

goTool/webui/index.html

@@ -55,11 +55,12 @@
     .badge-offline { background: #5c6570; color: #f0f3f5; }
     .badge.bg-secondary { background: #4a5560 !important; color: #f0f3f5; }
 
-    .mac {
+    .mac, .accel {
       font-family: ui-monospace, monospace;
       font-size: 0.85rem;
       color: var(--pp-accent);
     }
+    .accel-stale { color: var(--pp-text-muted); }
 
     .pp-table {
       --bs-table-color: var(--pp-text);
@@ -265,7 +266,9 @@
               <span class="badge bg-secondary" x-text="(state.clients || []).length + ' registered'"></span>
             </div>
           </div>
-          <p class="text-muted small px-3 pt-2 mb-0">Slaves per ESP-NOW — Master-Deadzone bleibt separat.</p>
+          <p class="text-muted small px-3 pt-2 mb-0">
+            Accel-Stream pro Slave per „Stream an“ aktivieren (~16&nbsp;ms ESP-NOW). Ohne Aktivierung keine Werte.
+          </p>
           <div class="card-body p-0 pt-2">
             <div class="table-responsive">
               <table class="table pp-table table-hover">
@@ -276,12 +279,14 @@
                     <th>Ver</th>
                     <th>Status</th>
                     <th>Deadzone</th>
+                    <th>Accel (LSB)</th>
+                    <th>Stream</th>
                     <th>Aktion</th>
                   </tr>
                 </thead>
                 <tbody>
                   <template x-if="!(state.clients || []).length">
-                    <tr><td colspan="6" class="text-muted text-center py-4">No clients</td></tr>
+                    <tr><td colspan="8" class="text-muted text-center py-4">No clients</td></tr>
                   </template>
                   <template x-for="c in (state.clients || [])" :key="c.id + c.mac">
                     <tr>
@@ -294,6 +299,20 @@
                               x-text="c.available ? 'available' : 'inactive'"></span>
                       </td>
                       <td x-text="c.deadzone != null ? c.deadzone : '—'"></td>
+                      <td>
+                        <span class="accel"
+                              :class="accelCellClass(c)"
+                              x-text="formatAccel(c)"
+                              :title="accelTitle(c)"></span>
+                      </td>
+                      <td>
+                        <button type="button"
+                                class="btn btn-sm"
+                                :class="c.accel_stream ? 'btn-warning' : 'btn-outline-success'"
+                                @click="setAccelStream(c.id, !c.accel_stream)"
+                                :disabled="busy || !state.uart_connected || !c.available"
+                                x-text="c.accel_stream ? 'Aus' : 'An'"></button>
+                      </td>
                       <td>
                         <div class="d-flex flex-wrap gap-1 align-items-center">
                           <input type="number" class="form-control form-control-sm dz-input"
@@ -496,6 +515,22 @@
           if (!hex || hex.length !== 12) return hex || '';
           return hex.match(/.{2}/g).join(':');
         },
+        formatAccel(c) {
+          if (!c?.accel_stream) return '—';
+          if (!c?.accel_valid) return '…';
+          return `${c.accel_x} / ${c.accel_y} / ${c.accel_z}`;
+        },
+        accelTitle(c) {
+          if (!c?.accel_stream) return 'Accel-Stream nicht aktiviert';
+          if (!c?.accel_valid) return 'Warte auf erste ESP-NOW Samples…';
+          const age = c.accel_age_ms != null ? `${c.accel_age_ms} ms alt` : '';
+          return `x=${c.accel_x} y=${c.accel_y} z=${c.accel_z} (raw LSB, ±2g)${age ? ' · ' + age : ''}`;
+        },
+        accelCellClass(c) {
+          if (!c?.accel_valid) return 'accel-stale';
+          if (c.accel_age_ms != null && c.accel_age_ms > 200) return 'accel-stale';
+          return '';
+        },
         formatSize(n) {
           if (n == null) return '';
           if (n < 1024) return n + ' B';
@@ -732,6 +767,44 @@
         async setMasterDeadzone() {
           await this.setDeadzone(0, this.masterDz);
         },
+        patchClientAccelStream(clientId, enabled) {
+          const clients = (this.state.clients || []).map((c) => {
+            if (c.id !== clientId) {
+              return c;
+            }
+            const next = { ...c, accel_stream: enabled };
+            if (!enabled) {
+              next.accel_valid = false;
+              next.accel_x = 0;
+              next.accel_y = 0;
+              next.accel_z = 0;
+              next.accel_age_ms = 0;
+            }
+            return next;
+          });
+          this.state = { ...this.state, clients };
+        },
+        async setAccelStream(clientId, enable) {
+          this.busy = true;
+          try {
+            const r = await fetch(`/api/clients/${clientId}/accel-stream`, {
+              method: 'PUT',
+              headers: { 'Content-Type': 'application/json' },
+              body: JSON.stringify({ enable: enable })
+            });
+            const data = await r.json();
+            if (!r.ok || !data.success) {
+              this.flash(data.error || `Accel-Stream Slave ${clientId} fehlgeschlagen`, false);
+              return;
+            }
+            this.patchClientAccelStream(clientId, !!data.enabled);
+            this.flash(`Slave ${clientId}: Accel-Stream ${data.enabled ? 'an' : 'aus'}`, true);
+          } catch (e) {
+            this.flash(String(e), false);
+          } finally {
+            this.busy = false;
+          }
+        },
         async setDeadzoneAll(deadzone) {
           if (deadzone == null || deadzone < 0) {
             this.flash('Ungültiger Deadzone-Wert', false);

main/CMakeLists.txt

@@ -18,7 +18,8 @@ idf_component_register(
   "cmd/cmd_version.c"
   "cmd/cmd_client_info.c"
   "cmd/cmd_accel_deadzone.c"
-  "cmd/cmd_accel_read.c"
+  "cmd/cmd_accel_snapshot.c"
+  "cmd/cmd_accel_stream.c"
   "cmd/cmd_espnow_unicast_test.c"
   "cmd/cmd_espnow_find_me.c"
   "cmd/cmd_restart.c"

main/README.md

@@ -115,6 +115,7 @@ Schema: `proto/esp_now_messages.proto`. Encode/decode: `esp_now_proto.c`. The ES
 | `ESPNOW_UNICAST_TEST` | Master → slave | `EspNowUnicastTest` (`seq`) |
 | `ESPNOW_FIND_ME` | Master → slave | `EspNowFindMe` (`client_id` filter) — LED locate sequence |
 | `ESPNOW_RESTART` | Master → slave | `EspNowRestart` (`client_id` filter) — reboot slave |
+| `ESPNOW_ACCEL_SAMPLE` | Slave → master | `EspNowAccelSample` (`slave_id`, `x`, `y`, `z` raw LSB) — ~every 16 ms |
 | `ESPNOW_OTA_START` | Master → slave (unicast) | `EspNowOtaStart` (`total_size`) |
 | `ESPNOW_OTA_PAYLOAD` | Master → slave | `EspNowOtaPayload` (`seq`, up to 200 B `data`) |
 | `ESPNOW_OTA_END` | Master → slave | `EspNowOtaEnd` |
@@ -217,7 +218,7 @@ Host and master speak nanopb-encoded `UartMessage` inside UART frames (byte 0 =
 | 21 | `OTA_SLAVE_PROGRESS` | Implemented (`cmd/cmd_ota_slave_progress.c`) — query per-slave ESP-NOW OTA progress |
 | 22 | `FIND_ME` | Implemented (`cmd/cmd_espnow_find_me.c`) — `client_id=0` local ring, `>0` ESP-NOW to slave |
 | 23 | `RESTART` | Implemented (`cmd/cmd_restart.c`) — `client_id=0` reboot master, `>0` ESP-NOW reboot slave |
-| 24 | `ACCEL_READ` | Implemented (`cmd/cmd_accel_read.c`) — on-demand BMA456 XYZ (raw LSB) |
+| 24 | `ACCEL_SNAPSHOT` | Implemented (`cmd/cmd_accel_snapshot.c`) — cached slave accel from ESP-NOW stream |
 
 Regenerate C code:
 
@@ -311,20 +312,20 @@ Sets the **software** deadzone used by `bosch456.c` when logging accel (see [BMA
 
 **Response:** `accel_deadzone_response` with applied `deadzone`, `success`, and `slaves_updated` (ESP-NOW count).
 
-### ACCEL_READ command
+### ACCEL_SNAPSHOT command
 
-Read the **current** BMA456 accelerometer sample on this node (master or slave with sensor). Values are raw LSB in the configured **±2g** range; they are **not** filtered by the software deadzone (unlike periodic `ACC X=…` logs in `bosch456.c`).
+Read **cached** accelerometer samples on the **master** (one entry per registered slave). Slaves send `ESPNOW_ACCEL_SAMPLE` to the master every **16 ms** (`esp_now_comm.c`); the master stores the latest value per client in `client_registry.c`.
 
-**Request:** framed `18` (`0x18`) only, or `18` + empty `accel_read_request`.
+**Request:** framed `18` (`0x18`) + optional `accel_snapshot_request` (`client_id`: `0` = all slaves, `>0` = one id).
 
-**Response:** `accel_read_response`:
+**Response:** `accel_snapshot_response.samples[]`:
 
 | Field | Meaning |
 |-------|---------|
-| `success` | `true` if BMA456 is ready and I2C read succeeded |
+| `client_id` | Slave id (registry) |
-| `x`, `y`, `z` | Raw accel LSB (`sint32`; meaningful only when `success`) |
+| `valid` | At least one ESP-NOW sample received since boot |
-
+| `x`, `y`, `z` | Raw BMA456 LSB (±2g) |
-If the sensor was not probed at boot (`bma456_is_ready()` false), `success` is `false` and axes are zero.
+| `age_ms` | Ms since last sample from that slave |
 
 Host:
 
@@ -332,7 +333,7 @@ Host:
 go run . -port /dev/ttyUSB0 accel
 ```
 
-Implementation: `bma456_read_accel()` in `bosch456.c` (mutex with the 10 Hz poll task), handler in `cmd/cmd_accel_read.c`.
+External API (`serve -api-addr :8081`) polls this command every 16 ms and streams JSON over WebSocket.
 
 ### ESPNOW_UNICAST_TEST command
 
@@ -479,7 +480,7 @@ Target: ESP32-S3. Close serial monitor on the UART adapter port before running `
 | `cmd/cmd_client_info.c/h` | CLIENT_INFO handler |
 | `client_registry.c/h` | Registered slave table |
 | `bosch456.c/h` | BMA456H I2C driver, accel poll, on-demand read, tap INT, deadzone filter |
-| `cmd/cmd_accel_read.c` | UART `ACCEL_READ` — current accel XYZ |
+| `cmd/cmd_accel_snapshot.c` | UART `ACCEL_SNAPSHOT` — cached slave accel |
 | `board_input.c/h` | Taster GPIO12, LiPo ADC on GPIO1 / GPIO12 |
 | `pod_settings.c/h` | NVS persistence (accel deadzone, …) |
 | `led_ring.c/h` | LED ring (digit display, progress bar) |

main/bosch456.c

@@ -2,7 +2,7 @@
  * BMA456H integration for Powerpod (ESP-IDF I2C master + Bosch SensorAPI).
  *
  * Polls accelerometer at 10 Hz; tap events arrive on BMA456_INT_GPIO.
- * Accel logging is filtered in software (deadzone); see ACCEL_DEADZONE UART command.
+ * Accel logging is filtered in software (deadzone); slaves stream samples via ESP-NOW.
  */
 
 #include "bosch456.h"

main/client_registry.c

@@ -241,6 +241,85 @@ size_t client_registry_set_accel_deadzone_all(uint32_t deadzone) {
   return n;
 }
 
+static void clear_client_accel(client_slot_t *slot) {
+  if (slot == NULL) {
+    return;
+  }
+  slot->info.accel_valid = false;
+  slot->info.accel_x = 0;
+  slot->info.accel_y = 0;
+  slot->info.accel_z = 0;
+  slot->info.accel_updated_at = 0;
+}
+
+esp_err_t client_registry_set_accel_stream(uint32_t client_id, bool enabled) {
+  for (size_t i = 0; i < CLIENT_REGISTRY_MAX; i++) {
+    if (!s_clients[i].active || s_clients[i].info.id != client_id) {
+      continue;
+    }
+    s_clients[i].info.accel_stream_enabled = enabled;
+    if (!enabled) {
+      clear_client_accel(&s_clients[i]);
+    }
+    return ESP_OK;
+  }
+  return ESP_ERR_NOT_FOUND;
+}
+
+esp_err_t client_registry_get_accel_stream(uint32_t client_id,
+                                           bool *enabled_out) {
+  if (enabled_out == NULL) {
+    return ESP_ERR_INVALID_ARG;
+  }
+  const client_info_t *info = client_registry_find_by_id(client_id);
+  if (info == NULL) {
+    return ESP_ERR_NOT_FOUND;
+  }
+  *enabled_out = info->accel_stream_enabled;
+  return ESP_OK;
+}
+
+size_t client_registry_set_accel_stream_all(bool enabled) {
+  size_t n = 0;
+  for (size_t i = 0; i < CLIENT_REGISTRY_MAX; i++) {
+    if (!s_clients[i].active) {
+      continue;
+    }
+    s_clients[i].info.accel_stream_enabled = enabled;
+    if (!enabled) {
+      clear_client_accel(&s_clients[i]);
+    }
+    n++;
+  }
+  return n;
+}
+
+esp_err_t client_registry_update_accel(const uint8_t mac[CLIENT_MAC_LEN],
+                                       uint32_t slave_id, int16_t x, int16_t y,
+                                       int16_t z) {
+  if (mac == NULL) {
+    return ESP_ERR_INVALID_ARG;
+  }
+
+  client_slot_t *slot = find_slot(mac);
+  if (slot == NULL) {
+    return ESP_ERR_NOT_FOUND;
+  }
+  if (slot->info.id != slave_id) {
+    return ESP_ERR_INVALID_ARG;
+  }
+  if (!slot->info.accel_stream_enabled) {
+    return ESP_ERR_INVALID_STATE;
+  }
+
+  slot->info.accel_x = x;
+  slot->info.accel_y = y;
+  slot->info.accel_z = z;
+  slot->info.accel_valid = true;
+  slot->info.accel_updated_at = now_ms();
+  return ESP_OK;
+}
+
 const client_info_t *client_registry_at(size_t index) {
   size_t n = 0;
   for (size_t i = 0; i < CLIENT_REGISTRY_MAX; i++) {

main/client_registry.h

@@ -21,6 +21,14 @@ typedef struct {
   uint32_t version;
   /** Accel deadzone in raw LSB per axis (master copy for ESP-NOW config). */
   uint32_t accel_deadzone;
+  /** Latest accel from slave ESP-NOW stream (master only). */
+  bool accel_valid;
+  int16_t accel_x;
+  int16_t accel_y;
+  int16_t accel_z;
+  uint32_t accel_updated_at;
+  /** Host-enabled ESP-NOW accel stream to master. */
+  bool accel_stream_enabled;
 } client_info_t;
 
 #define CLIENT_REGISTRY_DEFAULT_ACCEL_DEADZONE 100u
@@ -63,4 +71,13 @@ esp_err_t client_registry_get_accel_deadzone(uint32_t client_id,
 /** Push deadzone to all active registry entries; returns count updated. */
 size_t client_registry_set_accel_deadzone_all(uint32_t deadzone);
 
+/** Store latest accel sample from a slave (matched by sender MAC). */
+esp_err_t client_registry_update_accel(const uint8_t mac[CLIENT_MAC_LEN],
+                                       uint32_t slave_id, int16_t x, int16_t y,
+                                       int16_t z);
+
+esp_err_t client_registry_set_accel_stream(uint32_t client_id, bool enabled);
+esp_err_t client_registry_get_accel_stream(uint32_t client_id, bool *enabled_out);
+size_t client_registry_set_accel_stream_all(bool enabled);
+
 #endif

main/cmd/cmd_accel_read.c

@@ -1,34 +0,0 @@
-#include "bosch456.h"
-#include "cmd_accel_read.h"
-#include "uart_cmd.h"
-
-static const char *TAG = "[ACCEL_READ]";
-
-static void reply(bool success, int16_t x, int16_t y, int16_t z) {
-  alox_UartMessage response;
-  uart_cmd_init_response(&response, alox_MessageType_ACCEL_READ,
-                         alox_UartMessage_accel_read_response_tag);
-  response.payload.accel_read_response.success = success;
-  response.payload.accel_read_response.x = x;
-  response.payload.accel_read_response.y = y;
-  response.payload.accel_read_response.z = z;
-  uart_cmd_send(&response, TAG);
-}
-
-static void handle_accel_read(const uint8_t *data, size_t len) {
-  (void)data;
-  (void)len;
-
-  int16_t x = 0;
-  int16_t y = 0;
-  int16_t z = 0;
-  if (bma456_read_accel(&x, &y, &z) == ESP_OK) {
-    reply(true, x, y, z);
-    return;
-  }
-  reply(false, 0, 0, 0);
-}
-
-void cmd_accel_read_register(void) {
-  uart_cmd_register(alox_MessageType_ACCEL_READ, handle_accel_read);
-}

main/cmd/cmd_accel_read.h

@@ -1,6 +0,0 @@
-#ifndef CMD_ACCEL_READ_H
-#define CMD_ACCEL_READ_H
-
-void cmd_accel_read_register(void);
-
-#endif

main/cmd/cmd_accel_snapshot.c

@@ -0,0 +1,68 @@
+#include "client_registry.h"
+#include "cmd_accel_snapshot.h"
+#include "uart_cmd.h"
+
+static const char *TAG = "[ACCEL_SNAP]";
+
+static void fill_accel_snapshot(alox_AccelSnapshotResponse *out,
+                                uint32_t filter_client_id) {
+  if (out == NULL) {
+    return;
+  }
+
+  out->samples_count = 0;
+  size_t count = client_registry_count();
+
+  for (size_t i = 0; i < count; i++) {
+    const client_info_t *client = client_registry_at(i);
+    if (client == NULL) {
+      continue;
+    }
+    if (filter_client_id != 0 && client->id != filter_client_id) {
+      continue;
+    }
+    if (!client->accel_stream_enabled) {
+      continue;
+    }
+    if (out->samples_count >=
+        sizeof(out->samples) / sizeof(out->samples[0])) {
+      break;
+    }
+
+    alox_AccelSample *sample = &out->samples[out->samples_count++];
+    sample->client_id = client->id;
+    sample->valid = client->accel_valid;
+    sample->x = client->accel_x;
+    sample->y = client->accel_y;
+    sample->z = client->accel_z;
+    if (client->accel_valid) {
+      sample->age_ms = client_registry_ms_since(client->accel_updated_at);
+    }
+  }
+}
+
+static void handle_accel_snapshot(const uint8_t *data, size_t len) {
+  uint32_t filter_client_id = 0;
+
+  if (len > 0) {
+    alox_UartMessage req;
+    if (uart_cmd_decode(data, len, &req) == ESP_OK) {
+      alox_AccelSnapshotRequest *snap_req = UART_CMD_REQ(
+          &req, alox_UartMessage_accel_snapshot_request_tag, accel_snapshot_request);
+      if (snap_req != NULL) {
+        filter_client_id = snap_req->client_id;
+      }
+    }
+  }
+
+  alox_UartMessage response;
+  uart_cmd_init_response(&response, alox_MessageType_ACCEL_SNAPSHOT,
+                         alox_UartMessage_accel_snapshot_response_tag);
+  fill_accel_snapshot(&response.payload.accel_snapshot_response, filter_client_id);
+
+  uart_cmd_send(&response, TAG);
+}
+
+void cmd_accel_snapshot_register(void) {
+  uart_cmd_register(alox_MessageType_ACCEL_SNAPSHOT, handle_accel_snapshot);
+}

main/cmd/cmd_accel_snapshot.h

@@ -0,0 +1,6 @@
+#ifndef CMD_ACCEL_SNAPSHOT_H
+#define CMD_ACCEL_SNAPSHOT_H
+
+void cmd_accel_snapshot_register(void);
+
+#endif

main/cmd/cmd_accel_stream.c

@@ -0,0 +1,96 @@
+#include "client_registry.h"
+#include "cmd_accel_stream.h"
+#include "esp_log.h"
+#include "esp_now_comm.h"
+#include "uart_cmd.h"
+
+static const char *TAG = "[ACCEL_STREAM]";
+
+static void reply(bool enabled, uint32_t client_id, bool success,
+                  uint32_t slaves_updated) {
+  alox_UartMessage response;
+  uart_cmd_init_response(&response, alox_MessageType_ACCEL_STREAM,
+                         alox_UartMessage_accel_stream_response_tag);
+  response.payload.accel_stream_response.enabled = enabled;
+  response.payload.accel_stream_response.client_id = client_id;
+  response.payload.accel_stream_response.success = success;
+  response.payload.accel_stream_response.slaves_updated = slaves_updated;
+  uart_cmd_send(&response, TAG);
+}
+
+static esp_err_t push_stream_to_slave(const client_info_t *client, bool enable) {
+  if (client == NULL) {
+    return ESP_ERR_INVALID_ARG;
+  }
+  esp_err_t err = client_registry_set_accel_stream(client->id, enable);
+  if (err != ESP_OK) {
+    return err;
+  }
+  return esp_now_comm_send_accel_stream(client->mac, client->id, enable);
+}
+
+static void handle_accel_stream(const uint8_t *data, size_t len) {
+  alox_UartMessage uart_msg;
+  alox_AccelStreamRequest req = alox_AccelStreamRequest_init_zero;
+
+  if (uart_cmd_decode(data, len, &uart_msg) == ESP_OK) {
+    const alox_AccelStreamRequest *req_ptr = UART_CMD_REQ(
+        &uart_msg, alox_UartMessage_accel_stream_request_tag, accel_stream_request);
+    if (req_ptr != NULL) {
+      req = *req_ptr;
+    }
+  }
+
+  if (req.write) {
+    if (req.all_clients) {
+      size_t n = client_registry_set_accel_stream_all(req.enable);
+      uint32_t sent = 0;
+
+      for (size_t i = 0; i < client_registry_count(); i++) {
+        const client_info_t *client = client_registry_at(i);
+        if (client == NULL) {
+          continue;
+        }
+        if (esp_now_comm_send_accel_stream(client->mac, client->id,
+                                           req.enable) == ESP_OK) {
+          sent++;
+        }
+      }
+
+      ESP_LOGI(TAG, "accel stream %s for %u/%u slaves",
+               req.enable ? "on" : "off", (unsigned)sent, (unsigned)n);
+      reply(req.enable, 0, sent > 0, sent);
+      return;
+    }
+
+    if (req.client_id == 0) {
+      ESP_LOGW(TAG, "client_id required (or all_clients)");
+      reply(req.enable, 0, false, 0);
+      return;
+    }
+
+    const client_info_t *client = client_registry_find_by_id(req.client_id);
+    if (client == NULL) {
+      ESP_LOGW(TAG, "client id %lu not found", (unsigned long)req.client_id);
+      reply(req.enable, req.client_id, false, 0);
+      return;
+    }
+
+    esp_err_t err = push_stream_to_slave(client, req.enable);
+    reply(req.enable, req.client_id, err == ESP_OK, err == ESP_OK ? 1u : 0u);
+    return;
+  }
+
+  if (req.all_clients || req.client_id == 0) {
+    reply(false, 0, false, 0);
+    return;
+  }
+
+  bool enabled = false;
+  esp_err_t err = client_registry_get_accel_stream(req.client_id, &enabled);
+  reply(enabled, req.client_id, err == ESP_OK, 0);
+}
+
+void cmd_accel_stream_register(void) {
+  uart_cmd_register(alox_MessageType_ACCEL_STREAM, handle_accel_stream);
+}

main/cmd/cmd_accel_stream.h

@@ -0,0 +1,6 @@
+#ifndef CMD_ACCEL_STREAM_H
+#define CMD_ACCEL_STREAM_H
+
+void cmd_accel_stream_register(void);
+
+#endif

main/cmd/cmd_client_info.c

@@ -27,6 +27,7 @@ static bool encode_clients_list(pb_ostream_t *stream, const pb_field_t *field,
     proto.last_success_ping =
         client_registry_ms_since(client->last_success_ping_at);
     proto.version = client->version;
+    proto.accel_stream_enabled = client->accel_stream_enabled;
     proto.mac.funcs.encode = uart_cmd_encode_bytes;
     proto.mac.arg = &mac;
 

main/cmd/cmd_handler.c

@@ -48,8 +48,10 @@ static const char *message_type_name(uint16_t id) {
     return "FIND_ME";
   case alox_MessageType_RESTART:
     return "RESTART";
-  case alox_MessageType_ACCEL_READ:
+  case alox_MessageType_ACCEL_SNAPSHOT:
-    return "ACCEL_READ";
+    return "ACCEL_SNAPSHOT";
+  case alox_MessageType_ACCEL_STREAM:
+    return "ACCEL_STREAM";
   default:
     return "UNKNOWN";
   }

main/esp_now_comm.c

@@ -29,6 +29,7 @@
 #define ESPNOW_CLIENT_TIMEOUT_MS                                               \
   (ESPNOW_HEARTBEAT_INTERVAL_MS * ESPNOW_HEARTBEAT_MISS_COUNT)
 #define SLAVE_MASTER_LOST_MS (ESPNOW_HEARTBEAT_INTERVAL_MS * 5)
+#define ESPNOW_ACCEL_INTERVAL_MS 16
 
 static const uint8_t ESPNOW_BCAST[ESP_NOW_ETH_ALEN] = {0xff, 0xff, 0xff,
                                                        0xff, 0xff, 0xff};
@@ -39,6 +40,7 @@ static app_config_t s_config;
 static uint8_t s_wifi_channel;
 static uint8_t s_own_mac[ESP_NOW_ETH_ALEN];
 static bool s_slave_joined;
+static bool s_accel_stream_enabled;
 static uint8_t s_master_mac[ESP_NOW_ETH_ALEN];
 static uint32_t s_last_discover_ms;
 
@@ -111,6 +113,18 @@ static esp_err_t send_message(const uint8_t *dest_mac,
   return send_message_ex(dest_mac, msg, false);
 }
 
+static esp_err_t send_accel_sample(const uint8_t *dest_mac, uint32_t slave_id,
+                                   int16_t x, int16_t y, int16_t z) {
+  alox_EspNowMessage msg = alox_EspNowMessage_init_zero;
+  msg.type = alox_EspNowMessageType_ESPNOW_ACCEL_SAMPLE;
+  msg.which_payload = alox_EspNowMessage_accel_sample_tag;
+  msg.payload.accel_sample.slave_id = slave_id;
+  msg.payload.accel_sample.x = x;
+  msg.payload.accel_sample.y = y;
+  msg.payload.accel_sample.z = z;
+  return send_message(dest_mac, &msg);
+}
+
 static esp_err_t send_message_ex(const uint8_t *dest_mac,
                                  const alox_EspNowMessage *msg, bool wait_done) {
   uint8_t buf[ESPNOW_PB_MAX_SIZE];
@@ -151,6 +165,18 @@ static esp_err_t send_message_ex(const uint8_t *dest_mac,
   return err;
 }
 
+static esp_err_t send_accel_stream(const uint8_t *dest_mac, uint32_t client_id,
+                                   bool enable) {
+  alox_EspNowMessage msg = alox_EspNowMessage_init_zero;
+
+  msg.type = alox_EspNowMessageType_ESPNOW_SET_ACCEL_STREAM;
+  msg.which_payload = alox_EspNowMessage_accel_stream_tag;
+  msg.payload.accel_stream.enable = enable;
+  msg.payload.accel_stream.client_id = client_id;
+
+  return send_message(dest_mac, &msg);
+}
+
 static esp_err_t send_accel_deadzone(const uint8_t *dest_mac, uint32_t client_id,
                                      uint32_t deadzone) {
   alox_EspNowMessage msg = alox_EspNowMessage_init_zero;
@@ -338,6 +364,25 @@ esp_err_t esp_now_comm_send_unicast_test(const uint8_t mac[CLIENT_MAC_LEN],
   return err;
 }
 
+esp_err_t esp_now_comm_send_accel_stream(const uint8_t mac[CLIENT_MAC_LEN],
+                                         uint32_t client_id, bool enable) {
+  if (mac == NULL || !s_config.master) {
+    return ESP_ERR_INVALID_STATE;
+  }
+
+  char mac_str[18];
+  mac_to_str(mac, mac_str, sizeof(mac_str));
+  esp_err_t err = send_accel_stream(mac, client_id, enable);
+  if (err == ESP_OK) {
+    ESP_LOGI(TAG, "unicast SET_ACCEL_STREAM to %s: %s client_id=%lu", mac_str,
+             enable ? "on" : "off", (unsigned long)client_id);
+  } else {
+    ESP_LOGW(TAG, "unicast SET_ACCEL_STREAM to %s failed: %s", mac_str,
+             esp_err_to_name(err));
+  }
+  return err;
+}
+
 esp_err_t esp_now_comm_send_accel_deadzone(const uint8_t mac[CLIENT_MAC_LEN],
                                            uint32_t client_id, uint32_t deadzone) {
   if (mac == NULL || !s_config.master) {
@@ -377,6 +422,7 @@ static void send_presence(const uint8_t *dest_mac,
 
 static void slave_reset_join(void) {
   s_slave_joined = false;
+  s_accel_stream_enabled = false;
   memset(s_master_mac, 0, sizeof(s_master_mac));
   s_last_discover_ms = 0;
 }
@@ -426,6 +472,25 @@ static void handle_slave_find_me(const uint8_t *master_mac,
   led_ring_find_me();
 }
 
+static void handle_slave_accel_stream(const uint8_t *master_mac,
+                                      const alox_EspNowAccelStream *cfg) {
+  uint32_t my_id = s_own_mac[5];
+
+  if (cfg->client_id != 0 && cfg->client_id != my_id) {
+    return;
+  }
+
+  if (s_slave_joined && !mac_equal(master_mac, s_master_mac)) {
+    return;
+  }
+
+  s_accel_stream_enabled = cfg->enable;
+  char mac_str[18];
+  mac_to_str(master_mac, mac_str, sizeof(mac_str));
+  ESP_LOGI(TAG, "accel stream %s from master %s (id=%lu)",
+           cfg->enable ? "on" : "off", mac_str, (unsigned long)my_id);
+}
+
 static void handle_slave_accel_deadzone(const uint8_t *master_mac,
                                         const alox_EspNowAccelDeadzone *cfg) {
   uint32_t my_id = s_own_mac[5];
@@ -453,6 +518,23 @@ static void handle_slave_accel_deadzone(const uint8_t *master_mac,
   }
 }
 
+static void handle_master_accel_sample(const uint8_t mac[CLIENT_MAC_LEN],
+                                       const alox_EspNowAccelSample *sample) {
+  if (sample == NULL) {
+    return;
+  }
+
+  esp_err_t err = client_registry_update_accel(
+      mac, sample->slave_id, (int16_t)sample->x, (int16_t)sample->y,
+      (int16_t)sample->z);
+  if (err == ESP_ERR_NOT_FOUND) {
+    return;
+  }
+  if (err != ESP_OK) {
+    ESP_LOGW(TAG, "accel sample id mismatch from %02x:…:%02x", mac[0], mac[5]);
+  }
+}
+
 static void handle_client_presence(const alox_EspNowSlavePresence *presence,
                                    const uint8_t mac[CLIENT_MAC_LEN]) {
   if (presence->network != s_config.network) {
@@ -533,6 +615,30 @@ static void slave_check_master_timeout(void) {
   }
 }
 
+static void slave_accel_stream_task(void *param) {
+  (void)param;
+
+  ESP_LOGI(TAG, "slave accel stream task (interval %u ms)",
+           (unsigned)ESPNOW_ACCEL_INTERVAL_MS);
+
+  while (1) {
+    vTaskDelay(pdMS_TO_TICKS(ESPNOW_ACCEL_INTERVAL_MS));
+
+    if (!s_slave_joined || !s_accel_stream_enabled || !bma456_is_ready()) {
+      continue;
+    }
+
+    int16_t x = 0;
+    int16_t y = 0;
+    int16_t z = 0;
+    if (bma456_read_accel(&x, &y, &z) != ESP_OK) {
+      continue;
+    }
+
+    (void)send_accel_sample(s_master_mac, s_own_mac[5], x, y, z);
+  }
+}
+
 static void slave_heartbeat_task(void *param) {
   (void)param;
 
@@ -592,6 +698,12 @@ static void espnow_recv_cb(const esp_now_recv_info_t *info, const uint8_t *data,
     case alox_EspNowMessage_accel_deadzone_tag:
       handle_slave_accel_deadzone(info->src_addr, &msg.payload.accel_deadzone);
       break;
+    case alox_EspNowMessage_accel_stream_tag:
+      if (!s_slave_joined || !mac_equal(info->src_addr, s_master_mac)) {
+        break;
+      }
+      handle_slave_accel_stream(info->src_addr, &msg.payload.accel_stream);
+      break;
     case alox_EspNowMessage_find_me_tag:
       if (!s_slave_joined || !mac_equal(info->src_addr, s_master_mac)) {
         break;
@@ -639,6 +751,12 @@ static void espnow_recv_cb(const esp_now_recv_info_t *info, const uint8_t *data,
     return;
   }
 
+  if (msg.which_payload == alox_EspNowMessage_accel_sample_tag) {
+    ensure_peer(info->src_addr);
+    handle_master_accel_sample(info->src_addr, &msg.payload.accel_sample);
+    return;
+  }
+
   const alox_EspNowSlavePresence *presence = esp_now_proto_get_presence(&msg);
   if (presence != NULL) {
     /* Registry key is the ESP-NOW sender MAC, not the optional protobuf mac field. */
@@ -739,6 +857,11 @@ esp_err_t esp_now_comm_init(const app_config_t *config) {
       ESP_LOGE(TAG, "failed to create heartbeat task");
       return ESP_FAIL;
     }
+    if (xTaskCreate(slave_accel_stream_task, "espnow_accel", 4096, NULL, 5,
+                    NULL) != pdPASS) {
+      ESP_LOGE(TAG, "failed to create accel stream task");
+      return ESP_FAIL;
+    }
   }
 
   return ESP_OK;

main/esp_now_comm.h

@@ -7,6 +7,10 @@
 
 esp_err_t esp_now_comm_init(const app_config_t *config);
 
+/** Master: enable/disable accel ESP-NOW stream on one slave. */
+esp_err_t esp_now_comm_send_accel_stream(const uint8_t mac[CLIENT_MAC_LEN],
+                                         uint32_t client_id, bool enable);
+
 /** Master: unicast accel deadzone to one slave (client_id is echoed for filtering). */
 esp_err_t esp_now_comm_send_accel_deadzone(const uint8_t mac[CLIENT_MAC_LEN],
                                            uint32_t client_id, uint32_t deadzone);

main/powerpod.c

@@ -1,7 +1,8 @@
 #include "app_config.h"
 #include "cmd_handler.h"
 #include "cmd_accel_deadzone.h"
-#include "cmd_accel_read.h"
+#include "cmd_accel_snapshot.h"
+#include "cmd_accel_stream.h"
 #include "cmd_espnow_unicast_test.h"
 #include "cmd_espnow_find_me.h"
 #include "cmd_restart.h"
@@ -178,7 +179,8 @@ void app_main(void) {
     cmd_version_register();
     cmd_client_info_register();
     cmd_accel_deadzone_register();
-    cmd_accel_read_register();
+    cmd_accel_snapshot_register();
+    cmd_accel_stream_register();
     cmd_espnow_unicast_test_register();
     cmd_espnow_find_me_register();
     cmd_restart_register();

main/proto/esp_now_messages.pb.c

@@ -24,6 +24,12 @@ PB_BIND(alox_EspNowSlavePresence, alox_EspNowSlavePresence, AUTO)
 PB_BIND(alox_EspNowAccelDeadzone, alox_EspNowAccelDeadzone, AUTO)
 
 
+PB_BIND(alox_EspNowAccelStream, alox_EspNowAccelStream, AUTO)
+
+
+PB_BIND(alox_EspNowAccelSample, alox_EspNowAccelSample, AUTO)
+
+
 PB_BIND(alox_EspNowOtaStart, alox_EspNowOtaStart, AUTO)
 
 

main/proto/esp_now_messages.pb.h

@@ -22,7 +22,9 @@ typedef enum _alox_EspNowMessageType {
     alox_EspNowMessageType_ESPNOW_OTA_END = 8,
     alox_EspNowMessageType_ESPNOW_OTA_STATUS = 9,
     alox_EspNowMessageType_ESPNOW_FIND_ME = 10,
-    alox_EspNowMessageType_ESPNOW_RESTART = 11
+    alox_EspNowMessageType_ESPNOW_RESTART = 11,
+    alox_EspNowMessageType_ESPNOW_ACCEL_SAMPLE = 12,
+    alox_EspNowMessageType_ESPNOW_SET_ACCEL_STREAM = 13
 } alox_EspNowMessageType;
 
 /* Struct definitions */
@@ -59,6 +61,20 @@ typedef struct _alox_EspNowAccelDeadzone {
     uint32_t client_id; /* 0 = all slaves; otherwise only matching slave_id applies */
 } alox_EspNowAccelDeadzone;
 
+/* * Master → slave: enable/disable periodic accel ESP-NOW stream (~16 ms). */
+typedef struct _alox_EspNowAccelStream {
+    bool enable;
+    uint32_t client_id;
+} alox_EspNowAccelStream;
+
+/* * Slave → master: latest BMA456 sample (sent ~every 16 ms). */
+typedef struct _alox_EspNowAccelSample {
+    uint32_t slave_id;
+    int32_t x;
+    int32_t y;
+    int32_t z;
+} alox_EspNowAccelSample;
+
 /* Master → slave: begin OTA (erase inactive slot; slave replies ESPNOW_OTA_STATUS). */
 typedef struct _alox_EspNowOtaStart {
     uint32_t total_size;
@@ -98,6 +114,8 @@ typedef struct _alox_EspNowMessage {
         alox_EspNowOtaStatus ota_status;
         alox_EspNowFindMe find_me;
         alox_EspNowRestart restart;
+        alox_EspNowAccelSample accel_sample;
+        alox_EspNowAccelStream accel_stream;
     } payload;
 } alox_EspNowMessage;
 
@@ -108,8 +126,10 @@ extern "C" {
 
 /* Helper constants for enums */
 #define _alox_EspNowMessageType_MIN alox_EspNowMessageType_ESPNOW_UNKNOWN
-#define _alox_EspNowMessageType_MAX alox_EspNowMessageType_ESPNOW_RESTART
+#define _alox_EspNowMessageType_MAX alox_EspNowMessageType_ESPNOW_SET_ACCEL_STREAM
-#define _alox_EspNowMessageType_ARRAYSIZE ((alox_EspNowMessageType)(alox_EspNowMessageType_ESPNOW_RESTART+1))
+#define _alox_EspNowMessageType_ARRAYSIZE ((alox_EspNowMessageType)(alox_EspNowMessageType_ESPNOW_SET_ACCEL_STREAM+1))
+
+
 
 
 
@@ -131,6 +151,8 @@ extern "C" {
 #define alox_EspNowDiscover_init_default         {0}
 #define alox_EspNowSlavePresence_init_default    {0, {{NULL}, NULL}, 0, 0, 0, 0}
 #define alox_EspNowAccelDeadzone_init_default    {0, 0}
+#define alox_EspNowAccelStream_init_default      {0, 0}
+#define alox_EspNowAccelSample_init_default      {0, 0, 0, 0}
 #define alox_EspNowOtaStart_init_default         {0}
 #define alox_EspNowOtaPayload_init_default       {0, {0, {0}}}
 #define alox_EspNowOtaEnd_init_default           {0}
@@ -142,6 +164,8 @@ extern "C" {
 #define alox_EspNowDiscover_init_zero            {0}
 #define alox_EspNowSlavePresence_init_zero       {0, {{NULL}, NULL}, 0, 0, 0, 0}
 #define alox_EspNowAccelDeadzone_init_zero       {0, 0}
+#define alox_EspNowAccelStream_init_zero         {0, 0}
+#define alox_EspNowAccelSample_init_zero         {0, 0, 0, 0}
 #define alox_EspNowOtaStart_init_zero            {0}
 #define alox_EspNowOtaPayload_init_zero          {0, {0, {0}}}
 #define alox_EspNowOtaEnd_init_zero              {0}
@@ -161,6 +185,12 @@ extern "C" {
 #define alox_EspNowSlavePresence_used_tag        6
 #define alox_EspNowAccelDeadzone_deadzone_tag    1
 #define alox_EspNowAccelDeadzone_client_id_tag   2
+#define alox_EspNowAccelStream_enable_tag        1
+#define alox_EspNowAccelStream_client_id_tag     2
+#define alox_EspNowAccelSample_slave_id_tag      1
+#define alox_EspNowAccelSample_x_tag             2
+#define alox_EspNowAccelSample_y_tag             3
+#define alox_EspNowAccelSample_z_tag             4
 #define alox_EspNowOtaStart_total_size_tag       1
 #define alox_EspNowOtaPayload_seq_tag            1
 #define alox_EspNowOtaPayload_data_tag           2
@@ -179,6 +209,8 @@ extern "C" {
 #define alox_EspNowMessage_ota_status_tag        10
 #define alox_EspNowMessage_find_me_tag           11
 #define alox_EspNowMessage_restart_tag           12
+#define alox_EspNowMessage_accel_sample_tag      13
+#define alox_EspNowMessage_accel_stream_tag      14
 
 /* Struct field encoding specification for nanopb */
 #define alox_EspNowUnicastTest_FIELDLIST(X, a) \
@@ -217,6 +249,20 @@ X(a, STATIC,   SINGULAR, UINT32,   client_id,         2)
 #define alox_EspNowAccelDeadzone_CALLBACK NULL
 #define alox_EspNowAccelDeadzone_DEFAULT NULL
 
+#define alox_EspNowAccelStream_FIELDLIST(X, a) \
+X(a, STATIC,   SINGULAR, BOOL,     enable,            1) \
+X(a, STATIC,   SINGULAR, UINT32,   client_id,         2)
+#define alox_EspNowAccelStream_CALLBACK NULL
+#define alox_EspNowAccelStream_DEFAULT NULL
+
+#define alox_EspNowAccelSample_FIELDLIST(X, a) \
+X(a, STATIC,   SINGULAR, UINT32,   slave_id,          1) \
+X(a, STATIC,   SINGULAR, SINT32,   x,                 2) \
+X(a, STATIC,   SINGULAR, SINT32,   y,                 3) \
+X(a, STATIC,   SINGULAR, SINT32,   z,                 4)
+#define alox_EspNowAccelSample_CALLBACK NULL
+#define alox_EspNowAccelSample_DEFAULT NULL
+
 #define alox_EspNowOtaStart_FIELDLIST(X, a) \
 X(a, STATIC,   SINGULAR, UINT32,   total_size,        1)
 #define alox_EspNowOtaStart_CALLBACK NULL
@@ -252,7 +298,9 @@ X(a, STATIC,   ONEOF,    MESSAGE,  (payload,ota_payload,payload.ota_payload),
 X(a, STATIC,   ONEOF,    MESSAGE,  (payload,ota_end,payload.ota_end),   9) \
 X(a, STATIC,   ONEOF,    MESSAGE,  (payload,ota_status,payload.ota_status),  10) \
 X(a, STATIC,   ONEOF,    MESSAGE,  (payload,find_me,payload.find_me),  11) \
-X(a, STATIC,   ONEOF,    MESSAGE,  (payload,restart,payload.restart),  12)
+X(a, STATIC,   ONEOF,    MESSAGE,  (payload,restart,payload.restart),  12) \
+X(a, STATIC,   ONEOF,    MESSAGE,  (payload,accel_sample,payload.accel_sample),  13) \
+X(a, STATIC,   ONEOF,    MESSAGE,  (payload,accel_stream,payload.accel_stream),  14)
 #define alox_EspNowMessage_CALLBACK NULL
 #define alox_EspNowMessage_DEFAULT NULL
 #define alox_EspNowMessage_payload_discover_MSGTYPE alox_EspNowDiscover
@@ -266,6 +314,8 @@ X(a, STATIC,   ONEOF,    MESSAGE,  (payload,restart,payload.restart),  12)
 #define alox_EspNowMessage_payload_ota_status_MSGTYPE alox_EspNowOtaStatus
 #define alox_EspNowMessage_payload_find_me_MSGTYPE alox_EspNowFindMe
 #define alox_EspNowMessage_payload_restart_MSGTYPE alox_EspNowRestart
+#define alox_EspNowMessage_payload_accel_sample_MSGTYPE alox_EspNowAccelSample
+#define alox_EspNowMessage_payload_accel_stream_MSGTYPE alox_EspNowAccelStream
 
 extern const pb_msgdesc_t alox_EspNowUnicastTest_msg;
 extern const pb_msgdesc_t alox_EspNowFindMe_msg;
@@ -273,6 +323,8 @@ extern const pb_msgdesc_t alox_EspNowRestart_msg;
 extern const pb_msgdesc_t alox_EspNowDiscover_msg;
 extern const pb_msgdesc_t alox_EspNowSlavePresence_msg;
 extern const pb_msgdesc_t alox_EspNowAccelDeadzone_msg;
+extern const pb_msgdesc_t alox_EspNowAccelStream_msg;
+extern const pb_msgdesc_t alox_EspNowAccelSample_msg;
 extern const pb_msgdesc_t alox_EspNowOtaStart_msg;
 extern const pb_msgdesc_t alox_EspNowOtaPayload_msg;
 extern const pb_msgdesc_t alox_EspNowOtaEnd_msg;
@@ -286,6 +338,8 @@ extern const pb_msgdesc_t alox_EspNowMessage_msg;
 #define alox_EspNowDiscover_fields &alox_EspNowDiscover_msg
 #define alox_EspNowSlavePresence_fields &alox_EspNowSlavePresence_msg
 #define alox_EspNowAccelDeadzone_fields &alox_EspNowAccelDeadzone_msg
+#define alox_EspNowAccelStream_fields &alox_EspNowAccelStream_msg
+#define alox_EspNowAccelSample_fields &alox_EspNowAccelSample_msg
 #define alox_EspNowOtaStart_fields &alox_EspNowOtaStart_msg
 #define alox_EspNowOtaPayload_fields &alox_EspNowOtaPayload_msg
 #define alox_EspNowOtaEnd_fields &alox_EspNowOtaEnd_msg
@@ -297,6 +351,8 @@ extern const pb_msgdesc_t alox_EspNowMessage_msg;
 /* alox_EspNowMessage_size depends on runtime parameters */
 #define ALOX_ESP_NOW_MESSAGES_PB_H_MAX_SIZE      alox_EspNowOtaPayload_size
 #define alox_EspNowAccelDeadzone_size            12
+#define alox_EspNowAccelSample_size              24
+#define alox_EspNowAccelStream_size              8
 #define alox_EspNowDiscover_size                 6
 #define alox_EspNowFindMe_size                   6
 #define alox_EspNowOtaEnd_size                   0

main/proto/esp_now_messages.proto

@@ -17,6 +17,8 @@ enum EspNowMessageType {
   ESPNOW_OTA_STATUS = 9;
   ESPNOW_FIND_ME = 10;
   ESPNOW_RESTART = 11;
+  ESPNOW_ACCEL_SAMPLE = 12;
+  ESPNOW_SET_ACCEL_STREAM = 13;
 }
 
 message EspNowUnicastTest {
@@ -52,6 +54,20 @@ message EspNowAccelDeadzone {
   uint32 client_id = 2; // 0 = all slaves; otherwise only matching slave_id applies
 }
 
+/** Master → slave: enable/disable periodic accel ESP-NOW stream (~16 ms). */
+message EspNowAccelStream {
+  bool enable = 1;
+  uint32 client_id = 2;
+}
+
+/** Slave → master: latest BMA456 sample (sent ~every 16 ms). */
+message EspNowAccelSample {
+  uint32 slave_id = 1;
+  sint32 x = 2;
+  sint32 y = 3;
+  sint32 z = 4;
+}
+
 // Master → slave: begin OTA (erase inactive slot; slave replies ESPNOW_OTA_STATUS).
 message EspNowOtaStart {
   uint32 total_size = 1;
@@ -87,5 +103,7 @@ message EspNowMessage {
     EspNowOtaStatus ota_status = 10;
     EspNowFindMe find_me = 11;
     EspNowRestart restart = 12;
+    EspNowAccelSample accel_sample = 13;
+    EspNowAccelStream accel_stream = 14;
   }
 }

main/proto/uart_messages.pb.c

@@ -36,10 +36,19 @@ PB_BIND(alox_AccelDeadzoneRequest, alox_AccelDeadzoneRequest, AUTO)
 PB_BIND(alox_AccelDeadzoneResponse, alox_AccelDeadzoneResponse, AUTO)
 
 
-PB_BIND(alox_AccelReadRequest, alox_AccelReadRequest, AUTO)
+PB_BIND(alox_AccelStreamRequest, alox_AccelStreamRequest, AUTO)
 
 
-PB_BIND(alox_AccelReadResponse, alox_AccelReadResponse, AUTO)
+PB_BIND(alox_AccelStreamResponse, alox_AccelStreamResponse, AUTO)
+
+
+PB_BIND(alox_AccelSnapshotRequest, alox_AccelSnapshotRequest, AUTO)
+
+
+PB_BIND(alox_AccelSample, alox_AccelSample, AUTO)
+
+
+PB_BIND(alox_AccelSnapshotResponse, alox_AccelSnapshotResponse, 2)
 
 
 PB_BIND(alox_EspNowUnicastTestRequest, alox_EspNowUnicastTestRequest, AUTO)

main/proto/uart_messages.pb.h

@@ -28,7 +28,8 @@ typedef enum _alox_MessageType {
     alox_MessageType_OTA_SLAVE_PROGRESS = 21,
     alox_MessageType_FIND_ME = 22,
     alox_MessageType_RESTART = 23,
-    alox_MessageType_ACCEL_READ = 24
+    alox_MessageType_ACCEL_SNAPSHOT = 24,
+    alox_MessageType_ACCEL_STREAM = 25
 } alox_MessageType;
 
 /* Struct definitions */
@@ -55,6 +56,8 @@ typedef struct _alox_ClientInfo {
     uint32_t last_ping;
     uint32_t last_success_ping;
     uint32_t version;
+    /* * Master: ESP-NOW accel stream enabled for this slave. */
+    bool accel_stream_enabled;
 } alox_ClientInfo;
 
 typedef struct _alox_ClientInfoResponse {
@@ -89,17 +92,42 @@ typedef struct _alox_AccelDeadzoneResponse {
     uint32_t slaves_updated;
 } alox_AccelDeadzoneResponse;
 
-/* Host → device: read current BMA456 accelerometer sample (raw LSB, ±2g range). */
+/* Host → master: enable/disable slave accel ESP-NOW stream (~16 ms per slave).
-typedef struct _alox_AccelReadRequest {
+ write=false: read; write=true: apply. client_id 0 invalid for write (use >0 or all_clients). */
-    char dummy_field;
+typedef struct _alox_AccelStreamRequest {
-} alox_AccelReadRequest;
+    bool write;
+    bool enable;
+    uint32_t client_id;
+    bool all_clients;
+} alox_AccelStreamRequest;
 
-typedef struct _alox_AccelReadResponse {
+typedef struct _alox_AccelStreamResponse {
+    bool enabled;
+    uint32_t client_id;
     bool success;
+    uint32_t slaves_updated;
+} alox_AccelStreamResponse;
+
+/* Host → master: read cached accel samples from slaves (only while stream enabled).
+ client_id 0 = all registered slaves; otherwise one slave. */
+typedef struct _alox_AccelSnapshotRequest {
+    uint32_t client_id;
+} alox_AccelSnapshotRequest;
+
+typedef struct _alox_AccelSample {
+    uint32_t client_id;
+    bool valid;
     int32_t x;
     int32_t y;
     int32_t z;
-} alox_AccelReadResponse;
+    /* * Milliseconds since last ESP-NOW sample from this slave. */
+    uint32_t age_ms;
+} alox_AccelSample;
+
+typedef struct _alox_AccelSnapshotResponse {
+    pb_size_t samples_count;
+    alox_AccelSample samples[16];
+} alox_AccelSnapshotResponse;
 
 typedef struct _alox_EspNowUnicastTestRequest {
     uint32_t client_id;
@@ -231,8 +259,10 @@ typedef struct _alox_UartMessage {
         alox_EspNowFindMeResponse espnow_find_me_response;
         alox_RestartRequest restart_request;
         alox_RestartResponse restart_response;
-        alox_AccelReadRequest accel_read_request;
+        alox_AccelSnapshotRequest accel_snapshot_request;
-        alox_AccelReadResponse accel_read_response;
+        alox_AccelSnapshotResponse accel_snapshot_response;
+        alox_AccelStreamRequest accel_stream_request;
+        alox_AccelStreamResponse accel_stream_response;
     } payload;
 } alox_UartMessage;
 
@@ -243,8 +273,8 @@ extern "C" {
 
 /* Helper constants for enums */
 #define _alox_MessageType_MIN alox_MessageType_UNKNOWN
-#define _alox_MessageType_MAX alox_MessageType_ACCEL_READ
+#define _alox_MessageType_MAX alox_MessageType_ACCEL_STREAM
-#define _alox_MessageType_ARRAYSIZE ((alox_MessageType)(alox_MessageType_ACCEL_READ+1))
+#define _alox_MessageType_ARRAYSIZE ((alox_MessageType)(alox_MessageType_ACCEL_STREAM+1))
 
 #define alox_UartMessage_type_ENUMTYPE alox_MessageType
 
@@ -271,6 +301,9 @@ extern "C" {
 
 
 
+
+
+
 
 
 
@@ -280,14 +313,17 @@ extern "C" {
 #define alox_Ack_init_default                    {0}
 #define alox_EchoPayload_init_default            {{{NULL}, NULL}}
 #define alox_VersionResponse_init_default        {0, {{NULL}, NULL}, {{NULL}, NULL}}
-#define alox_ClientInfo_init_default             {0, 0, 0, {{NULL}, NULL}, 0, 0, 0}
+#define alox_ClientInfo_init_default             {0, 0, 0, {{NULL}, NULL}, 0, 0, 0, 0}
 #define alox_ClientInfoResponse_init_default     {{{NULL}, NULL}}
 #define alox_ClientInput_init_default            {0, 0, 0, 0}
 #define alox_ClientInputResponse_init_default    {{{NULL}, NULL}}
 #define alox_AccelDeadzoneRequest_init_default   {0, 0, 0, 0}
 #define alox_AccelDeadzoneResponse_init_default  {0, 0, 0, 0}
-#define alox_AccelReadRequest_init_default       {0}
+#define alox_AccelStreamRequest_init_default     {0, 0, 0, 0}
-#define alox_AccelReadResponse_init_default      {0, 0, 0, 0}
+#define alox_AccelStreamResponse_init_default    {0, 0, 0, 0}
+#define alox_AccelSnapshotRequest_init_default   {0}
+#define alox_AccelSample_init_default            {0, 0, 0, 0, 0, 0}
+#define alox_AccelSnapshotResponse_init_default  {0, {alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default, alox_AccelSample_init_default}}
 #define alox_EspNowUnicastTestRequest_init_default {0, 0}
 #define alox_EspNowUnicastTestResponse_init_default {0, 0}
 #define alox_LedRingProgressRequest_init_default {0, 0, 0, 0, 0, 0, 0, 0, 0}
@@ -307,14 +343,17 @@ extern "C" {
 #define alox_Ack_init_zero                       {0}
 #define alox_EchoPayload_init_zero               {{{NULL}, NULL}}
 #define alox_VersionResponse_init_zero           {0, {{NULL}, NULL}, {{NULL}, NULL}}
-#define alox_ClientInfo_init_zero                {0, 0, 0, {{NULL}, NULL}, 0, 0, 0}
+#define alox_ClientInfo_init_zero                {0, 0, 0, {{NULL}, NULL}, 0, 0, 0, 0}
 #define alox_ClientInfoResponse_init_zero        {{{NULL}, NULL}}
 #define alox_ClientInput_init_zero               {0, 0, 0, 0}
 #define alox_ClientInputResponse_init_zero       {{{NULL}, NULL}}
 #define alox_AccelDeadzoneRequest_init_zero      {0, 0, 0, 0}
 #define alox_AccelDeadzoneResponse_init_zero     {0, 0, 0, 0}
-#define alox_AccelReadRequest_init_zero          {0}
+#define alox_AccelStreamRequest_init_zero        {0, 0, 0, 0}
-#define alox_AccelReadResponse_init_zero         {0, 0, 0, 0}
+#define alox_AccelStreamResponse_init_zero       {0, 0, 0, 0}
+#define alox_AccelSnapshotRequest_init_zero      {0}
+#define alox_AccelSample_init_zero               {0, 0, 0, 0, 0, 0}
+#define alox_AccelSnapshotResponse_init_zero     {0, {alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero, alox_AccelSample_init_zero}}
 #define alox_EspNowUnicastTestRequest_init_zero  {0, 0}
 #define alox_EspNowUnicastTestResponse_init_zero {0, 0}
 #define alox_LedRingProgressRequest_init_zero    {0, 0, 0, 0, 0, 0, 0, 0, 0}
@@ -343,6 +382,7 @@ extern "C" {
 #define alox_ClientInfo_last_ping_tag            5
 #define alox_ClientInfo_last_success_ping_tag    6
 #define alox_ClientInfo_version_tag              7
+#define alox_ClientInfo_accel_stream_enabled_tag 8
 #define alox_ClientInfoResponse_clients_tag      1
 #define alox_ClientInput_id_tag                  1
 #define alox_ClientInput_lage_x_tag              2
@@ -357,10 +397,22 @@ extern "C" {
 #define alox_AccelDeadzoneResponse_client_id_tag 2
 #define alox_AccelDeadzoneResponse_success_tag   3
 #define alox_AccelDeadzoneResponse_slaves_updated_tag 4
-#define alox_AccelReadResponse_success_tag       1
+#define alox_AccelStreamRequest_write_tag        1
-#define alox_AccelReadResponse_x_tag             2
+#define alox_AccelStreamRequest_enable_tag       2
-#define alox_AccelReadResponse_y_tag             3
+#define alox_AccelStreamRequest_client_id_tag    3
-#define alox_AccelReadResponse_z_tag             4
+#define alox_AccelStreamRequest_all_clients_tag  4
+#define alox_AccelStreamResponse_enabled_tag     1
+#define alox_AccelStreamResponse_client_id_tag   2
+#define alox_AccelStreamResponse_success_tag     3
+#define alox_AccelStreamResponse_slaves_updated_tag 4
+#define alox_AccelSnapshotRequest_client_id_tag  1
+#define alox_AccelSample_client_id_tag           1
+#define alox_AccelSample_valid_tag               2
+#define alox_AccelSample_x_tag                   3
+#define alox_AccelSample_y_tag                   4
+#define alox_AccelSample_z_tag                   5
+#define alox_AccelSample_age_ms_tag              6
+#define alox_AccelSnapshotResponse_samples_tag   1
 #define alox_EspNowUnicastTestRequest_client_id_tag 1
 #define alox_EspNowUnicastTestRequest_seq_tag    2
 #define alox_EspNowUnicastTestResponse_success_tag 1
@@ -424,8 +476,10 @@ extern "C" {
 #define alox_UartMessage_espnow_find_me_response_tag 20
 #define alox_UartMessage_restart_request_tag     21
 #define alox_UartMessage_restart_response_tag    22
-#define alox_UartMessage_accel_read_request_tag  23
+#define alox_UartMessage_accel_snapshot_request_tag 23
-#define alox_UartMessage_accel_read_response_tag 24
+#define alox_UartMessage_accel_snapshot_response_tag 24
+#define alox_UartMessage_accel_stream_request_tag 25
+#define alox_UartMessage_accel_stream_response_tag 26
 
 /* Struct field encoding specification for nanopb */
 #define alox_UartMessage_FIELDLIST(X, a) \
@@ -451,8 +505,10 @@ X(a, STATIC,   ONEOF,    MESSAGE,  (payload,espnow_find_me_request,payload.espno
 X(a, STATIC,   ONEOF,    MESSAGE,  (payload,espnow_find_me_response,payload.espnow_find_me_response),  20) \
 X(a, STATIC,   ONEOF,    MESSAGE,  (payload,restart_request,payload.restart_request),  21) \
 X(a, STATIC,   ONEOF,    MESSAGE,  (payload,restart_response,payload.restart_response),  22) \
-X(a, STATIC,   ONEOF,    MESSAGE,  (payload,accel_read_request,payload.accel_read_request),  23) \
+X(a, STATIC,   ONEOF,    MESSAGE,  (payload,accel_snapshot_request,payload.accel_snapshot_request),  23) \
-X(a, STATIC,   ONEOF,    MESSAGE,  (payload,accel_read_response,payload.accel_read_response),  24)
+X(a, STATIC,   ONEOF,    MESSAGE,  (payload,accel_snapshot_response,payload.accel_snapshot_response),  24) \
+X(a, STATIC,   ONEOF,    MESSAGE,  (payload,accel_stream_request,payload.accel_stream_request),  25) \
+X(a, STATIC,   ONEOF,    MESSAGE,  (payload,accel_stream_response,payload.accel_stream_response),  26)
 #define alox_UartMessage_CALLBACK NULL
 #define alox_UartMessage_DEFAULT NULL
 #define alox_UartMessage_payload_ack_payload_MSGTYPE alox_Ack
@@ -476,8 +532,10 @@ X(a, STATIC,   ONEOF,    MESSAGE,  (payload,accel_read_response,payload.accel_re
 #define alox_UartMessage_payload_espnow_find_me_response_MSGTYPE alox_EspNowFindMeResponse
 #define alox_UartMessage_payload_restart_request_MSGTYPE alox_RestartRequest
 #define alox_UartMessage_payload_restart_response_MSGTYPE alox_RestartResponse
-#define alox_UartMessage_payload_accel_read_request_MSGTYPE alox_AccelReadRequest
+#define alox_UartMessage_payload_accel_snapshot_request_MSGTYPE alox_AccelSnapshotRequest
-#define alox_UartMessage_payload_accel_read_response_MSGTYPE alox_AccelReadResponse
+#define alox_UartMessage_payload_accel_snapshot_response_MSGTYPE alox_AccelSnapshotResponse
+#define alox_UartMessage_payload_accel_stream_request_MSGTYPE alox_AccelStreamRequest
+#define alox_UartMessage_payload_accel_stream_response_MSGTYPE alox_AccelStreamResponse
 
 #define alox_Ack_FIELDLIST(X, a) \
 
@@ -503,7 +561,8 @@ X(a, STATIC,   SINGULAR, BOOL,     used,              3) \
 X(a, CALLBACK, SINGULAR, BYTES,    mac,               4) \
 X(a, STATIC,   SINGULAR, UINT32,   last_ping,         5) \
 X(a, STATIC,   SINGULAR, UINT32,   last_success_ping,   6) \
-X(a, STATIC,   SINGULAR, UINT32,   version,           7)
+X(a, STATIC,   SINGULAR, UINT32,   version,           7) \
+X(a, STATIC,   SINGULAR, BOOL,     accel_stream_enabled,   8)
 #define alox_ClientInfo_CALLBACK pb_default_field_callback
 #define alox_ClientInfo_DEFAULT NULL
 
@@ -543,18 +602,42 @@ X(a, STATIC,   SINGULAR, UINT32,   slaves_updated,    4)
 #define alox_AccelDeadzoneResponse_CALLBACK NULL
 #define alox_AccelDeadzoneResponse_DEFAULT NULL
 
-#define alox_AccelReadRequest_FIELDLIST(X, a) \
+#define alox_AccelStreamRequest_FIELDLIST(X, a) \
+X(a, STATIC,   SINGULAR, BOOL,     write,             1) \
+X(a, STATIC,   SINGULAR, BOOL,     enable,            2) \
+X(a, STATIC,   SINGULAR, UINT32,   client_id,         3) \
+X(a, STATIC,   SINGULAR, BOOL,     all_clients,       4)
+#define alox_AccelStreamRequest_CALLBACK NULL
+#define alox_AccelStreamRequest_DEFAULT NULL
 
-#define alox_AccelReadRequest_CALLBACK NULL
+#define alox_AccelStreamResponse_FIELDLIST(X, a) \
-#define alox_AccelReadRequest_DEFAULT NULL
+X(a, STATIC,   SINGULAR, BOOL,     enabled,           1) \
+X(a, STATIC,   SINGULAR, UINT32,   client_id,         2) \
+X(a, STATIC,   SINGULAR, BOOL,     success,           3) \
+X(a, STATIC,   SINGULAR, UINT32,   slaves_updated,    4)
+#define alox_AccelStreamResponse_CALLBACK NULL
+#define alox_AccelStreamResponse_DEFAULT NULL
 
-#define alox_AccelReadResponse_FIELDLIST(X, a) \
+#define alox_AccelSnapshotRequest_FIELDLIST(X, a) \
-X(a, STATIC,   SINGULAR, BOOL,     success,           1) \
+X(a, STATIC,   SINGULAR, UINT32,   client_id,         1)
-X(a, STATIC,   SINGULAR, SINT32,   x,                 2) \
+#define alox_AccelSnapshotRequest_CALLBACK NULL
-X(a, STATIC,   SINGULAR, SINT32,   y,                 3) \
+#define alox_AccelSnapshotRequest_DEFAULT NULL
-X(a, STATIC,   SINGULAR, SINT32,   z,                 4)
+
-#define alox_AccelReadResponse_CALLBACK NULL
+#define alox_AccelSample_FIELDLIST(X, a) \
-#define alox_AccelReadResponse_DEFAULT NULL
+X(a, STATIC,   SINGULAR, UINT32,   client_id,         1) \
+X(a, STATIC,   SINGULAR, BOOL,     valid,             2) \
+X(a, STATIC,   SINGULAR, SINT32,   x,                 3) \
+X(a, STATIC,   SINGULAR, SINT32,   y,                 4) \
+X(a, STATIC,   SINGULAR, SINT32,   z,                 5) \
+X(a, STATIC,   SINGULAR, UINT32,   age_ms,            6)
+#define alox_AccelSample_CALLBACK NULL
+#define alox_AccelSample_DEFAULT NULL
+
+#define alox_AccelSnapshotResponse_FIELDLIST(X, a) \
+X(a, STATIC,   REPEATED, MESSAGE,  samples,           1)
+#define alox_AccelSnapshotResponse_CALLBACK NULL
+#define alox_AccelSnapshotResponse_DEFAULT NULL
+#define alox_AccelSnapshotResponse_samples_MSGTYPE alox_AccelSample
 
 #define alox_EspNowUnicastTestRequest_FIELDLIST(X, a) \
 X(a, STATIC,   SINGULAR, UINT32,   client_id,         1) \
@@ -669,8 +752,11 @@ extern const pb_msgdesc_t alox_ClientInput_msg;
 extern const pb_msgdesc_t alox_ClientInputResponse_msg;
 extern const pb_msgdesc_t alox_AccelDeadzoneRequest_msg;
 extern const pb_msgdesc_t alox_AccelDeadzoneResponse_msg;
-extern const pb_msgdesc_t alox_AccelReadRequest_msg;
+extern const pb_msgdesc_t alox_AccelStreamRequest_msg;
-extern const pb_msgdesc_t alox_AccelReadResponse_msg;
+extern const pb_msgdesc_t alox_AccelStreamResponse_msg;
+extern const pb_msgdesc_t alox_AccelSnapshotRequest_msg;
+extern const pb_msgdesc_t alox_AccelSample_msg;
+extern const pb_msgdesc_t alox_AccelSnapshotResponse_msg;
 extern const pb_msgdesc_t alox_EspNowUnicastTestRequest_msg;
 extern const pb_msgdesc_t alox_EspNowUnicastTestResponse_msg;
 extern const pb_msgdesc_t alox_LedRingProgressRequest_msg;
@@ -698,8 +784,11 @@ extern const pb_msgdesc_t alox_OtaSlaveProgressResponse_msg;
 #define alox_ClientInputResponse_fields &alox_ClientInputResponse_msg
 #define alox_AccelDeadzoneRequest_fields &alox_AccelDeadzoneRequest_msg
 #define alox_AccelDeadzoneResponse_fields &alox_AccelDeadzoneResponse_msg
-#define alox_AccelReadRequest_fields &alox_AccelReadRequest_msg
+#define alox_AccelStreamRequest_fields &alox_AccelStreamRequest_msg
-#define alox_AccelReadResponse_fields &alox_AccelReadResponse_msg
+#define alox_AccelStreamResponse_fields &alox_AccelStreamResponse_msg
+#define alox_AccelSnapshotRequest_fields &alox_AccelSnapshotRequest_msg
+#define alox_AccelSample_fields &alox_AccelSample_msg
+#define alox_AccelSnapshotResponse_fields &alox_AccelSnapshotResponse_msg
 #define alox_EspNowUnicastTestRequest_fields &alox_EspNowUnicastTestRequest_msg
 #define alox_EspNowUnicastTestResponse_fields &alox_EspNowUnicastTestResponse_msg
 #define alox_LedRingProgressRequest_fields &alox_LedRingProgressRequest_msg
@@ -723,11 +812,14 @@ extern const pb_msgdesc_t alox_OtaSlaveProgressResponse_msg;
 /* alox_ClientInfo_size depends on runtime parameters */
 /* alox_ClientInfoResponse_size depends on runtime parameters */
 /* alox_ClientInputResponse_size depends on runtime parameters */
-#define ALOX_UART_MESSAGES_PB_H_MAX_SIZE         alox_OtaSlaveProgressResponse_size
+#define ALOX_UART_MESSAGES_PB_H_MAX_SIZE         alox_AccelSnapshotResponse_size
 #define alox_AccelDeadzoneRequest_size           16
 #define alox_AccelDeadzoneResponse_size          20
-#define alox_AccelReadRequest_size               0
+#define alox_AccelSample_size                    32
-#define alox_AccelReadResponse_size              20
+#define alox_AccelSnapshotRequest_size           6
+#define alox_AccelSnapshotResponse_size          544
+#define alox_AccelStreamRequest_size             12
+#define alox_AccelStreamResponse_size            16
 #define alox_Ack_size                            0
 #define alox_ClientInput_size                    22
 #define alox_EspNowFindMeRequest_size            6

main/proto/uart_messages.proto

@@ -22,7 +22,8 @@ enum MessageType {
   OTA_SLAVE_PROGRESS = 21;
   FIND_ME = 22;
   RESTART = 23;
-  ACCEL_READ = 24;
+  ACCEL_SNAPSHOT = 24;
+  ACCEL_STREAM = 25;
 }
 
 message UartMessage {
@@ -49,8 +50,10 @@ message UartMessage {
     EspNowFindMeResponse espnow_find_me_response = 20;
     RestartRequest restart_request = 21;
     RestartResponse restart_response = 22;
-    AccelReadRequest accel_read_request = 23;
+    AccelSnapshotRequest accel_snapshot_request = 23;
-    AccelReadResponse accel_read_response = 24;
+    AccelSnapshotResponse accel_snapshot_response = 24;
+    AccelStreamRequest accel_stream_request = 25;
+    AccelStreamResponse accel_stream_response = 26;
   }
 }
 
@@ -75,6 +78,8 @@ message ClientInfo {
   uint32 last_ping = 5;
   uint32 last_success_ping = 6;
   uint32 version = 7;
+  /** Master: ESP-NOW accel stream enabled for this slave. */
+  bool accel_stream_enabled = 8;
 }
 
 message ClientInfoResponse { 
@@ -109,14 +114,40 @@ message AccelDeadzoneResponse {
   uint32 slaves_updated = 4;
 }
 
-// Host → device: read current BMA456 accelerometer sample (raw LSB, ±2g range).
+// Host → master: enable/disable slave accel ESP-NOW stream (~16 ms per slave).
-message AccelReadRequest {}
+// write=false: read; write=true: apply. client_id 0 invalid for write (use >0 or all_clients).
+message AccelStreamRequest {
+  bool write = 1;
+  bool enable = 2;
+  uint32 client_id = 3;
+  bool all_clients = 4;
+}
 
-message AccelReadResponse {
+message AccelStreamResponse {
-  bool success = 1;
+  bool enabled = 1;
-  sint32 x = 2;
+  uint32 client_id = 2;
-  sint32 y = 3;
+  bool success = 3;
-  sint32 z = 4;
+  uint32 slaves_updated = 4;
+}
+
+// Host → master: read cached accel samples from slaves (only while stream enabled).
+// client_id 0 = all registered slaves; otherwise one slave.
+message AccelSnapshotRequest {
+  uint32 client_id = 1;
+}
+
+message AccelSample {
+  uint32 client_id = 1;
+  bool valid = 2;
+  sint32 x = 3;
+  sint32 y = 4;
+  sint32 z = 5;
+  /** Milliseconds since last ESP-NOW sample from this slave. */
+  uint32 age_ms = 6;
+}
+
+message AccelSnapshotResponse {
+  repeated AccelSample samples = 1 [(nanopb).max_count = 16];
 }
 
 message EspNowUnicastTestRequest {

main/uart.h

@@ -9,8 +9,12 @@
 
 #define UART_NUM UART_NUM_1
 #define UART_BAUD_RATE 921600
-#define UART_TXD_PIN 3
+// #define UART_TXD_PIN 3
-#define UART_RXD_PIN 2
+// #define UART_RXD_PIN 2
+
+#define UART_TXD_PIN 2
+#define UART_RXD_PIN 3
+
 
 #define UART_BUF_SIZE 2048
 #define START_MARKER 0xAA