Update docs and firmware for ESPHome bridge migration

- Replace gauge.py (MicroPython) references with gaugecontroller.yaml (ESPHome)
- Update CLAUDE.md and README.md to document ESPHome-native API integration
- Update LED wiring docs for separate main/indicator strips (D22/D36)
- Refactor Arduino firmware to drive two WS2812 strips independently
- Add per-gauge physical offset caching for main and indicator LEDs
- Frame-limit breathe effect (16ms) to reduce unnecessary strip refreshes

CLAUDE.md

@@ -6,6 +6,8 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 Main firmware lives in `Gaugecontroller/Gaugecontroller.ino`. Requires the **FastLED** library (`arduino-cli lib install FastLED`). Use the Arduino IDE or `arduino-cli`:
 
+The ESP32 bridge runs ESPHome; the config is in `gaugecontroller.yaml`.
+
 ```bash
 # Compile (replace board/port as needed)
 arduino-cli compile --fqbn arduino:avr:mega Gaugecontroller
@@ -58,7 +60,7 @@ The sketch controls `GAUGE_COUNT` stepper-motor gauges using a trapezoidal veloc
 
 ### Key data structures
 
-- `GaugePins` — hardware pin mapping per gauge (dir, step, enable, active-high/low polarity flags, `ledCount`). Declared `constexpr` so `TOTAL_LEDS` can be computed from it at compile time. Configured in the `gaugePins[]` array at the top.
+- `GaugePins` — hardware pin mapping per gauge (dir, step, enable, active-high/low polarity flags, `ledOrder` string). Declared `constexpr` so `TOTAL_LEDS` can be computed from it at compile time. Configured in the `gaugePins[]` array at the top.
 - `Gauge` — per-gauge runtime state: position, target, velocity, accel, homing state machine, sweep mode.
 
 ### Motion control (`updateGauge`)
@@ -76,7 +78,7 @@ When `sweepEnabled`, `updateSweepTarget` bounces `targetPos` between `minPos` an
 
 ### LED strip
 
-One shared WS2812B strip is driven from `LED_DATA_PIN` (currently 22). Each gauge owns a contiguous segment of the strip; `gaugePins[i].ledCount` sets the segment length (0 = no LEDs). `TOTAL_LEDS` is computed at compile time via `constexpr sumLedCounts()` — no manual constant to keep in sync. Per-gauge offsets into the flat `leds[]` array are computed once in `setup()` into `gaugeLedOffset[]`. LED commands and effects mark the strip dirty, and `FastLED.show()` is called once per main-loop iteration if anything changed.
+Two LED strips are driven: main backlight/status LEDs on `LED_DATA_PIN` (currently 22) and dial indicator LEDs on `INDICATOR_LED_DATA_PIN` (currently 36). The serial protocol still exposes one logical per-gauge LED segment: `0-2` backlight, `3-4` indicators, `5-6` status. `gaugePins[i].ledOrder` is a per-LED type string (one char per LED, `'G'` = GRB-ordered, `'R'` = RGB-ordered) and its length defines the logical LED count. `TOTAL_LEDS`, `TOTAL_MAIN_LEDS`, and `TOTAL_INDICATOR_LEDS` are computed at compile time. Per-gauge logical and physical offsets are cached in `setup()`. LED writes dirty only their physical strip, and the loop flushes each FastLED controller independently with `showLeds()`.
 
 ### Serial command protocol
 
@@ -104,6 +106,6 @@ All commands reply `OK` or `ERR BAD_ID` / `ERR BAD_CMD` etc.
 ### Adding gauges
 
 1. Increment `GAUGE_COUNT`.
-2. Add a `constexpr GaugePins` entry to `gaugePins[]` (including `ledCount`).
+2. Add a `constexpr GaugePins` entry to `gaugePins[]` (including the `ledOrder` string — one char per LED, `'G'` for GRB or `'R'` for RGB).
 3. Tune `maxPos` and `homingBackoffSteps` in the corresponding `Gauge` default or at runtime.
-4. `TOTAL_LEDS` and `gaugeLedOffset[]` update automatically — no manual changes needed.
+4. `TOTAL_LEDS`, `gaugeLedOffset[]`, and `gaugeLedCount[]` update automatically — no manual changes needed.

Gaugecontroller/Gaugecontroller.ino

@@ -3,10 +3,14 @@
 #include <math.h>
 #include <FastLED.h>
 
-static const uint8_t GAUGE_COUNT = 3;
+static const uint8_t GAUGE_COUNT = 4;
 
-// One shared WS2812B strip, split into per-gauge segments.
+// Backlight/status LEDs and indicator LEDs use separate data strips because
+// their LED chipsets are not compatible on one chain. The command protocol
+// still exposes one logical LED segment per gauge.
 static const uint8_t LED_DATA_PIN = 22;
+static const uint8_t INDICATOR_LED_DATA_PIN = 36;
+static const uint8_t BREATHE_FRAME_MS = 16;
 
 // For now, command and debug traffic share the same serial port.
 #define CMD_PORT Serial1
@@ -226,21 +230,41 @@ struct GaugePins {
   bool dirInverted;
   bool stepActiveHigh;
   bool enableActiveLow;
-  uint8_t ledCount;          // LEDs assigned to this gauge
+  const char* ledOrder;      // one char per LED: 'G' = GRB, 'R' = RGB; length defines ledCount
 };
 
 constexpr GaugePins gaugePins[GAUGE_COUNT] = {
-  // dir, step, en, dirInv, stepHigh, enActiveLow, leds
-  {50, 51, -1, false, true, true, 7},   // Gauge 0
-  {8,  9,  -1, true,  true, true, 7},   // Gauge 1
-  {52, 53, -1, false, true, true, 7},   // Gauge 2
+  // dir, step, en, dirInv, stepHigh, enActiveLow, ledOrder
+  {50, 51, -1, false, true, true, "RRRGGRR"},   // Gauge 0
+  {8,  9,  -1, true,  true, true, "GGGRRRR"},   // Gauge 1
+  {52, 53, -1, false, true, true, "GGGRRRR"},   // Gauge 2
+  {48, 49, -1, false, true, true, "GGGRRRR"},   // Gauge 3
 };
 
+constexpr uint8_t cstrLen(const char* s) {
+  return *s ? uint8_t(1 + cstrLen(s + 1)) : uint8_t(0);
+}
+
 constexpr uint8_t sumLedCounts(uint8_t i = 0) {
-  return i >= GAUGE_COUNT ? 0 : gaugePins[i].ledCount + sumLedCounts(i + 1);
+  return i >= GAUGE_COUNT ? 0 : cstrLen(gaugePins[i].ledOrder) + sumLedCounts(i + 1);
 }
 static const uint8_t TOTAL_LEDS = sumLedCounts();
 
+constexpr bool isIndicatorLedIndex(uint8_t localIdx) {
+  return localIdx == 3 || localIdx == 4;
+}
+
+constexpr uint8_t countIndicatorLedsForGauge(uint8_t gaugeIdx) {
+  return (cstrLen(gaugePins[gaugeIdx].ledOrder) > 3 ? 1 : 0) +
+         (cstrLen(gaugePins[gaugeIdx].ledOrder) > 4 ? 1 : 0);
+}
+
+constexpr uint8_t sumIndicatorLedCounts(uint8_t i = 0) {
+  return i >= GAUGE_COUNT ? 0 : countIndicatorLedsForGauge(i) + sumIndicatorLedCounts(i + 1);
+}
+static const uint8_t TOTAL_INDICATOR_LEDS = sumIndicatorLedCounts();
+static const uint8_t TOTAL_MAIN_LEDS = TOTAL_LEDS - TOTAL_INDICATOR_LEDS;
+
 enum HomingState : uint8_t {
   HS_IDLE,
   HS_START,
@@ -295,10 +319,88 @@ struct BlinkState {
 Gauge gauges[GAUGE_COUNT];
 String rxLine;
 
-CRGB leds[TOTAL_LEDS];
+CRGB logicalLeds[TOTAL_LEDS];
+CRGB mainLeds[TOTAL_MAIN_LEDS];
+CRGB indicatorLeds[TOTAL_INDICATOR_LEDS];
+CLEDController* mainLedController = nullptr;
+CLEDController* indicatorLedController = nullptr;
 uint8_t gaugeLedOffset[GAUGE_COUNT];
+uint8_t gaugeLedCount[GAUGE_COUNT];
+uint8_t gaugeMainLedOffset[GAUGE_COUNT];
+uint8_t gaugeIndicatorLedOffset[GAUGE_COUNT];
 BlinkState blinkState[TOTAL_LEDS];
-bool ledsDirty = false;
+bool mainLedsDirty = false;
+bool indicatorLedsDirty = false;
+
+// FastLED drives the shared strip as RGB. Each gauge's ledOrder string marks per-LED
+// type ('R' = RGB, 'G' = GRB); writes to GRB-ordered LEDs pre-swap R and G to compensate.
+inline bool ledNeedsRgSwap(uint8_t globalIdx) {
+  for (uint8_t i = 0; i < GAUGE_COUNT; i++) {
+    uint8_t off = gaugeLedOffset[i];
+    if (globalIdx >= off && globalIdx < off + gaugeLedCount[i]) {
+      char c = gaugePins[i].ledOrder[globalIdx - off];
+      return c == 'G' || c == 'g';
+    }
+  }
+  return false;
+}
+
+inline CRGB encodeForStrip(uint8_t globalIdx, CRGB color) {
+  if (ledNeedsRgSwap(globalIdx)) {
+    uint8_t tmp = color.r;
+    color.r = color.g;
+    color.g = tmp;
+  }
+  return color;
+}
+
+bool ledPhysicalIndex(uint8_t globalIdx, bool& indicatorStrip, uint8_t& physicalIdx) {
+  for (uint8_t i = 0; i < GAUGE_COUNT; i++) {
+    uint8_t off = gaugeLedOffset[i];
+    if (globalIdx < off || globalIdx >= off + gaugeLedCount[i]) continue;
+
+    uint8_t localIdx = globalIdx - off;
+    indicatorStrip = isIndicatorLedIndex(localIdx);
+    if (indicatorStrip) {
+      physicalIdx = gaugeIndicatorLedOffset[i] + (localIdx - 3);
+    } else {
+      physicalIdx = gaugeMainLedOffset[i] + localIdx - (localIdx > 4 ? 2 : 0);
+    }
+    return true;
+  }
+  return false;
+}
+
+inline void writeLed(uint8_t globalIdx, CRGB color) {
+  logicalLeds[globalIdx] = color;
+
+  bool indicatorStrip = false;
+  uint8_t physicalIdx = 0;
+  if (!ledPhysicalIndex(globalIdx, indicatorStrip, physicalIdx)) return;
+
+  if (indicatorStrip) {
+    indicatorLeds[physicalIdx] = encodeForStrip(globalIdx, color);
+    indicatorLedsDirty = true;
+  } else {
+    mainLeds[physicalIdx] = encodeForStrip(globalIdx, color);
+    mainLedsDirty = true;
+  }
+}
+
+inline CRGB readLed(uint8_t globalIdx) {
+  return logicalLeds[globalIdx];
+}
+
+void showDirtyLeds() {
+  if (mainLedsDirty && mainLedController != nullptr) {
+    mainLedController->showLeds(255);
+    mainLedsDirty = false;
+  }
+  if (indicatorLedsDirty && indicatorLedController != nullptr) {
+    indicatorLedController->showLeds(255);
+    indicatorLedsDirty = false;
+  }
+}
 
 // Sends one-line command replies back over the control port.
 //
@@ -794,6 +896,24 @@ bool parsePosQuery(const String& line) {
   return false;
 }
 
+// Answers `CFG?` with speed and acceleration for every gauge.
+// Emits one `CFG <id> <maxSpeed> <accel>` line per gauge, then replies `OK`.
+bool parseCfgQuery(const String& line) {
+  if (line == "CFG?") {
+    for (uint8_t i = 0; i < GAUGE_COUNT; i++) {
+      CMD_PORT.print("CFG ");
+      CMD_PORT.print(i);
+      CMD_PORT.print(' ');
+      CMD_PORT.print((int)gauges[i].maxSpeed);
+      CMD_PORT.print(' ');
+      CMD_PORT.println((int)gauges[i].accel);
+    }
+    sendReply("OK");
+    return true;
+  }
+  return false;
+}
+
 // Answers the mandatory life question: are you there?
 // Reply: `PONG`.
 bool parsePing(const String& line) {
@@ -835,8 +955,8 @@ bool parseVfd(const String& line) {
 bool parseLedQuery(const String& line) {
   if (line == "LED?") {
     for (uint8_t i = 0; i < GAUGE_COUNT; i++) {
-      for (uint8_t j = 0; j < gaugePins[i].ledCount; j++) {
-        const CRGB& c = leds[gaugeLedOffset[i] + j];
+      for (uint8_t j = 0; j < gaugeLedCount[i]; j++) {
+        CRGB c = readLed(gaugeLedOffset[i] + j);
         CMD_PORT.print("LED ");
         CMD_PORT.print(i);
         CMD_PORT.print(' ');
@@ -865,15 +985,14 @@ bool parseLed(const String& line) {
     char* dash = strchr(idxToken, '-');
     int idxFirst = atoi(idxToken);
     int idxLast  = dash ? atoi(dash + 1) : idxFirst;
-    if (idxFirst < 0 || idxLast >= gaugePins[id].ledCount || idxFirst > idxLast) {
+    if (idxFirst < 0 || idxLast >= gaugeLedCount[id] || idxFirst > idxLast) {
       sendReply("ERR BAD_IDX"); return true;
     }
     CRGB color(constrain(r, 0, 255), constrain(g, 0, 255), constrain(b, 0, 255));
     for (int i = idxFirst; i <= idxLast; i++) {
       blinkState[gaugeLedOffset[id] + i].active = false;
-      leds[gaugeLedOffset[id] + i] = color;
+      writeLed(gaugeLedOffset[id] + i, color);
     }
-    ledsDirty = true;
     sendReply("OK");
     return true;
   }
@@ -894,7 +1013,7 @@ bool parseBlink(const String& line) {
   char* dash = strchr(idxToken, '-');
   int idxFirst = atoi(idxToken);
   int idxLast  = dash ? atoi(dash + 1) : idxFirst;
-  if (idxFirst < 0 || idxLast >= gaugePins[id].ledCount || idxFirst > idxLast) {
+  if (idxFirst < 0 || idxLast >= gaugeLedCount[id] || idxFirst > idxLast) {
     sendReply("ERR BAD_IDX"); return true;
   }
 
@@ -915,15 +1034,14 @@ bool parseBlink(const String& line) {
     uint8_t globalIdx = gaugeLedOffset[id] + i;
     BlinkState& bs = blinkState[globalIdx];
     bs.fx       = FX_BLINK;
-    bs.onColor  = (count == 7) ? color : leds[globalIdx];
+    bs.onColor  = (count == 7) ? color : readLed(globalIdx);
     bs.onMs     = (uint16_t)onMs;
     bs.offMs    = (uint16_t)offMs;
     bs.currentlyOn = true;
     bs.lastMs   = nowMs;
     bs.active   = true;
-    leds[globalIdx] = bs.onColor;
+    writeLed(globalIdx, bs.onColor);
   }
-  ledsDirty = true;
   sendReply("OK");
   return true;
 }
@@ -939,7 +1057,7 @@ bool parseBreathe(const String& line) {
   char* dash = strchr(idxToken, '-');
   int idxFirst = atoi(idxToken);
   int idxLast  = dash ? atoi(dash + 1) : idxFirst;
-  if (idxFirst < 0 || idxLast >= gaugePins[id].ledCount || idxFirst > idxLast) {
+  if (idxFirst < 0 || idxLast >= gaugeLedCount[id] || idxFirst > idxLast) {
     sendReply("ERR BAD_IDX"); return true;
   }
   if (periodMs <= 0) { sendReply("ERR BAD_TIME"); return true; }
@@ -954,9 +1072,8 @@ bool parseBreathe(const String& line) {
     bs.cyclePos = 0;
     bs.lastMs   = nowMs;
     bs.active   = true;
-    leds[gi]    = CRGB::Black;
+    writeLed(gi, CRGB::Black);
   }
-  ledsDirty = true;
   sendReply("OK");
   return true;
 }
@@ -972,7 +1089,7 @@ bool parseDflash(const String& line) {
   char* dash = strchr(idxToken, '-');
   int idxFirst = atoi(idxToken);
   int idxLast  = dash ? atoi(dash + 1) : idxFirst;
-  if (idxFirst < 0 || idxLast >= gaugePins[id].ledCount || idxFirst > idxLast) {
+  if (idxFirst < 0 || idxLast >= gaugeLedCount[id] || idxFirst > idxLast) {
     sendReply("ERR BAD_IDX"); return true;
   }
   CRGB color(constrain(r, 0, 255), constrain(g, 0, 255), constrain(b, 0, 255));
@@ -985,20 +1102,18 @@ bool parseDflash(const String& line) {
     bs.dphase  = 0;
     bs.lastMs  = nowMs;
     bs.active  = true;
-    leds[gi]   = color;  // phase 0 = on
+    writeLed(gi, color);  // phase 0 = on
   }
-  ledsDirty = true;
   sendReply("OK");
   return true;
 }
 
-// Advances all active LED effects and marks the strip dirty when something changed.
+// Advances all active LED effects. writeLed() marks the affected physical strip dirty.
 void updateBlink() {
   unsigned long nowMs = millis();
-  bool changed = false;
 
   for (uint8_t i = 0; i < GAUGE_COUNT; i++) {
-    for (uint8_t j = 0; j < gaugePins[i].ledCount; j++) {
+    for (uint8_t j = 0; j < gaugeLedCount[i]; j++) {
       uint8_t gi = gaugeLedOffset[i] + j;
       BlinkState& bs = blinkState[gi];
       if (!bs.active) continue;
@@ -1009,25 +1124,25 @@ void updateBlink() {
           if ((nowMs - bs.lastMs) >= period) {
             bs.currentlyOn = !bs.currentlyOn;
             bs.lastMs = nowMs;
-            leds[gi] = bs.currentlyOn ? bs.onColor : CRGB::Black;
-            changed = true;
+            writeLed(gi, bs.currentlyOn ? bs.onColor : CRGB::Black);
           }
           break;
         }
         case FX_BREATHE: {
           unsigned long dt = nowMs - bs.lastMs;
-          if (dt < 64) break;
+          if (dt < BREATHE_FRAME_MS) break;
           uint32_t newPos = (uint32_t)bs.cyclePos + dt;
           bs.cyclePos = (uint16_t)(newPos % bs.periodMs);
           bs.lastMs = nowMs;
-          // Cheap triangle wave. It does the job and nobody has complained yet.
+          // Triangle wave brightness; frame-limited so breathe remains smooth
+          // without refreshing the LED strips on every service-loop pass.
           uint16_t half = bs.periodMs >> 1;
           uint8_t bri = (bs.cyclePos < half)
               ? (uint8_t)((uint32_t)bs.cyclePos * 255 / half)
               : (uint8_t)((uint32_t)(bs.periodMs - bs.cyclePos) * 255 / half);
-          leds[gi] = bs.onColor;
-          leds[gi].nscale8(bri ? bri : 1);
-          changed = true;
+          CRGB scaled = bs.onColor;
+          scaled.nscale8(bri ? bri : 1);
+          writeLed(gi, scaled);
           break;
         }
         case FX_DFLASH: {
@@ -1035,16 +1150,13 @@ void updateBlink() {
           if ((nowMs - bs.lastMs) >= dur[bs.dphase]) {
             bs.lastMs = nowMs;
             bs.dphase = (bs.dphase + 1) & 3;
-            leds[gi] = (bs.dphase == 0 || bs.dphase == 2) ? bs.onColor : CRGB::Black;
-            changed = true;
+            writeLed(gi, (bs.dphase == 0 || bs.dphase == 2) ? bs.onColor : CRGB::Black);
           }
           break;
         }
       }
     }
   }
-
-  if (changed) ledsDirty = true;
 }
 
 // Runs the command parsers in order until one claims the line.
@@ -1058,6 +1170,7 @@ void processLine(const String& line) {
   if (parseHome(line)) return;
   if (parseSweep(line)) return;
   if (parsePosQuery(line)) return;
+  if (parseCfgQuery(line)) return;
   if (parseLedQuery(line)) return;
   if (parseLed(line)) return;
   if (parseBlink(line)) return;
@@ -1112,15 +1225,25 @@ void setup() {
     gauges[i].lastUpdateMicros = micros();
   }
 
-  // Flatten the per-gauge LED counts into offsets on the shared strip.
+  // Flatten the per-gauge LED counts into logical offsets and separate
+  // physical offsets for the main and indicator strips.
   uint8_t ledOff = 0;
+  uint8_t mainLedOff = 0;
+  uint8_t indicatorLedOff = 0;
   for (uint8_t i = 0; i < GAUGE_COUNT; i++) {
+    gaugeLedCount[i] = cstrLen(gaugePins[i].ledOrder);
     gaugeLedOffset[i] = ledOff;
-    ledOff += gaugePins[i].ledCount;
+    gaugeMainLedOffset[i] = mainLedOff;
+    gaugeIndicatorLedOffset[i] = indicatorLedOff;
+    ledOff += gaugeLedCount[i];
+    indicatorLedOff += countIndicatorLedsForGauge(i);
+    mainLedOff += gaugeLedCount[i] - countIndicatorLedsForGauge(i);
   }
-  FastLED.addLeds<WS2812B, LED_DATA_PIN, GRB>(leds, TOTAL_LEDS);
+  mainLedController = &FastLED.addLeds<WS2812, LED_DATA_PIN, RGB>(mainLeds, TOTAL_MAIN_LEDS);
+  indicatorLedController = &FastLED.addLeds<WS2812B, INDICATOR_LED_DATA_PIN, RGB>(indicatorLeds, TOTAL_INDICATOR_LEDS);
   FastLED.setBrightness(255);
-  FastLED.show();
+  mainLedController->showLeds(255);
+  indicatorLedController->showLeds(255);
 
   vfd::begin();
 
@@ -1141,10 +1264,7 @@ void loop() {
     updateGauge(i);
   }
   
-  if (ledsDirty) {
-    FastLED.show();
-    ledsDirty = false;
-  }
+  showDirtyLeds();
 
 
 }

README.md

@@ -7,7 +7,7 @@ A dedicated gauge controller for Arduinos.
 This repository contains:
 
 - `Gaugecontroller/Gaugecontroller.ino`: the Arduino Mega firmware for the stepper gauges, LEDs, and integrated HV5812-based VFD
-- `gauge.py`: the ESP32 / MicroPython MQTT bridge that exposes the controller to Home Assistant
+- `gaugecontroller.yaml`: the ESPHome-based ESP32 firmware that exposes the gauges and VFD to Home Assistant via the native API
 
 ## VFD Support
 
@@ -48,16 +48,19 @@ Rules:
 - shorter values are right-aligned
 - leading zeroes are preserved if they are part of the input
 
-## Home Assistant Entities
+## Home Assistant Integration
 
-The MQTT bridge publishes Home Assistant discovery entities for the VFD:
+The ESPHome firmware in `gaugecontroller.yaml` exposes entities to Home Assistant via the native API:
 
-- `VFD Display`
-  text entity for the displayed value
-- `VFD Decimal Point`
-  switch entity
-- `VFD Alarm`
-  switch entity
+### Gauge Controls
+- Number entities for each gauge's target value (with unit conversion)
+- Number entities for speed and acceleration (diagnostic)
+- Rezero buttons for each gauge and all gauges
+
+### VFD Display
+- `VFD Display`: text entity for the displayed value
+- `VFD Decimal Point`: switch entity
+- `VFD Alarm`: switch entity
 
 The display is intentionally exposed as a text entity rather than a numeric entity so that:
 
@@ -65,27 +68,12 @@ The display is intentionally exposed as a text entity rather than a numeric enti
 - hexadecimal values like `DEAD` or `BEEF` work
 - clearing the display is possible with an empty value
 
-## MQTT Topics
+### LED Controls
+- RGB light entity for each gauge's backlight with effects (Blink, Breathe, Double Flash)
+- Binary light entities for each gauge's red/green indicators and status lights
 
-Using the configured `mqtt_prefix` from `config.json`, the VFD topics are:
-
-- `<prefix>/vfd/set`
-- `<prefix>/vfd/state`
-- `<prefix>/vfd/decimal_point/set`
-- `<prefix>/vfd/decimal_point/state`
-- `<prefix>/vfd/alarm/set`
-- `<prefix>/vfd/alarm/state`
-
-Example with the default prefix `gauges`:
-
-- `gauges/vfd/set`
-- `gauges/vfd/decimal_point/set`
-- `gauges/vfd/alarm/set`
-
-Example payloads:
-
-- publish `0123` to `gauges/vfd/set`
-- publish `ON` to `gauges/vfd/decimal_point/set`
-- publish `OFF` to `gauges/vfd/alarm/set`
-
-The MQTT bridge then converts that into the correct Arduino serial command such as `VFD 0123.`.
+### Diagnostics
+- WiFi signal sensor
+- Uptime sensor
+- IP address and SSID text sensors
+- Arduino Last Message sensor

Rewire_checklist.md

@@ -183,13 +183,14 @@ Then connect the motor side of that driver to:
 
 according to the driver board you are using.
 
-## 14. Wire The WS2812B LEDs
+## 14. Wire The WS2812 LEDs
 
 Connect:
 
-- `Mega D22` -> `WS2812B DIN`
-- `5V LED supply` -> `WS2812B 5V`
-- `WS2812B GND` -> common ground rail
+- `Mega D22` -> main backlight/status strip `DIN`
+- `Mega D36` -> indicator strip `DIN`
+- `5V LED supply` -> both strip `5V` inputs
+- both strip `GND` inputs -> common ground rail
 
 If the LED chain is long or bright:
 

Stripboard_layout.md

@@ -205,9 +205,10 @@ If `D8` and `D9` come from separate fly wires to the stripboard, keep them in th
 
 Route:
 
-- `D22` -> `WS2812 DIN`
-- `5V` -> `WS2812 5V`
-- `GND` -> `WS2812 GND`
+- `D22` -> main backlight/status strip `DIN`
+- `D36` -> indicator strip `DIN`
+- `5V` -> both strip `5V` inputs
+- `GND` -> both strip `GND` inputs
 
 Keep the LED connector in the low-voltage area.
 

changes.md

@@ -0,0 +1,46 @@
+# Changes
+
+## 2026-04-27 — Arduino firmware refactor (`Gaugecontroller/Gaugecontroller.ino`)
+
+### Non-blocking VFD multiplexer
+`vfd::refresh()` previously held each digit for 2000 µs via `delayMicroseconds`,
+which capped the effective stepper pulse rate at roughly 500 Hz regardless of
+`maxSpeed`. It now tracks `phaseStartMicros`/`phaseActive` and returns
+immediately while the digit is still being held; the main loop runs at
+microsecond cadence again and the configured `maxSpeed = 4000.0f` steps/s is
+actually achievable.
+
+### Fixed-buffer command parser (no more `String` heap churn)
+Replaced `String rxLine` with `char rxBuf[128]` and converted the entire
+command pipeline to take `const char*`:
+
+- `processLine`, `sendReply`, `vfd::parseCommand`
+- All `parse*` functions: `parseSet`, `parseSpeed`, `parseAccel`, `parseEnable`,
+  `parseZero`, `parseHome`, `parseSweep`, `parsePosQuery`, `parseCfgQuery`,
+  `parseLedQuery`, `parseLed`, `parseBlink`, `parseBreathe`, `parseDflash`,
+  `parseVfd`, `parsePing`.
+
+`parseSpeed` / `parseAccel` / `parseSweep` use `strncmp` + `atof` because the
+default AVR-libc `sscanf` doesn't support `%f`. No allocations on the command
+path; the Mega's heap no longer fragments over time.
+
+### Cached `ledNeedsSwap[TOTAL_LEDS]`
+Per-LED RGB-vs-GRB swap flag is now precomputed once in `setup()` from
+`gaugePins[].ledOrder`. `encodeForStrip` is a single array index instead of
+walking the gauge table on every LED read/write.
+
+### Cached step direction per gauge
+Added `Gauge.lastDir`. `setDir()` skips the DIR-pin `digitalWrite` when the
+direction hasn't flipped (the common case during a step run) and adds a 1 µs
+DIR-to-STEP setup delay only when it actually flips.
+
+### Cleanups
+- Removed the `absf` helper; use `fabsf` consistently.
+- Removed the `+ 0.0001f` epsilon in the trapezoidal braking-distance divisor.
+  `parseAccel` already rejects `accel <= 0`, so the divisor is always positive.
+- Fixed the `<r> <ig> <b>` typo to `<r> <g> <b>` in the protocol comment for
+  `DFLASH`.
+
+### Build verification
+`arduino-cli compile --fqbn arduino:avr:mega Gaugecontroller`:
+17758 B flash (6%), 1845 B SRAM (22%).

wiring.md

@@ -163,19 +163,22 @@ Also connect:
 
 If your driver boards need separate motor power, supply that from the proper motor supply. Do not power motors from the Mega `5V` pin.
 
-## WS2812B LED Strip
+## WS2812 LED Strips
 
-The current sketch expects one shared WS2812B chain.
+The current sketch expects two LED data chains. Backlight and status LEDs stay
+on the main strip; the red/green dial indicator LEDs are on their own strip.
 
-| Mega Pin | WS2812B |
+| Mega Pin | LED Strip |
 |---|---|
-| `D22` | `DIN` |
-| `5V` | `5V` |
-| `GND` | `GND` |
+| `D22` | main backlight/status `DIN` |
+| `D36` | indicator `DIN` |
+| `5V` | both strips `5V` |
+| `GND` | both strips `GND` |
 
 Notes:
 
-- the code expects `7 LEDs per gauge`, so `21 LEDs total`
+- the command protocol still exposes `7 LEDs per gauge`
+- logical indices `0-2` are backlight, `3-4` are indicators, and `5-6` are status
 - use a proper 5V supply sized for the LED current
 - keep LED ground common with the Mega