State limitation: lastExhaustState records only the last command this controller sent. There is no valve-position sensor or physical feedback, so the displayed state may differ from the actual valve position if the remote, power, wiring, or actuator did not respond.

Text
TacomaDialController/
├── TacomaDialController.ino
└── ui_assets.h

• home_240_jpg and home_240_jpg_len
• exhaust_open_240_jpg and exhaust_open_240_jpg_len
• exhaust_quiet_240_jpg and exhaust_quiet_240_jpg_len

1. Create or open the sketch TacomaDialController.ino.
2. Click the small tab/menu control at the upper-right of the Arduino editor.
3. Choose New Tab.
4. Name the tab exactly ui_assets.h.
5. Open the download link above, copy the entire generated header, and paste it into the new tab. Alternatively, download it and place it directly in the same folder as the .ino file.
6. Keep #include "ui_assets.h" near the top of the main .ino file.

• Arduino IDE 2.x
• M5Stack board package: 3.2.2 or newer
• Tools → Board: M5Stack → M5 Dial (some versions display M5Dial without a space)
• Library Manager: M5Dial 1.0.3 or newer, accepting its M5Unified and M5GFX dependencies
• USB CDC On Boot: Enabled if required for serial upload/monitoring by the installed ESP32-S3 package
• Serial Monitor: 115200 baud

Cpp
M5Dial.Display.drawJpg(jpegArray, jpegLength, 0, 0);

Cpp
#include <Arduino.h>
#include <M5Dial.h>
#include "ui_assets.h"

// Verified PORT.B wiring. Do not swap.
static constexpr uint8_t EXHAUST_OPEN_PIN  = 1;  // White cable, PC817 -> remote S2
static constexpr uint8_t EXHAUST_QUIET_PIN = 2;  // Yellow cable, PC817 -> remote S1

static constexpr uint32_t OUTPUT_PULSE_MS   = 500;
static constexpr uint32_t STATUS_SCREEN_MS  = 1200;
static constexpr uint32_t DOUBLE_CLICK_MS   = 450;
static constexpr uint32_t CLICK_DEBOUNCE_MS = 60;
static constexpr uint32_t CLOCK_REFRESH_MS  = 250;

static constexpr uint16_t COLOR_BG    = TFT_BLACK;
static constexpr uint16_t COLOR_WHITE = TFT_WHITE;
static constexpr uint16_t COLOR_RED   = 0xF800;

enum class ExhaustState : uint8_t {
  QUIET,
  OPEN
};

enum class ScreenMode : uint8_t {
  HOME,
  OPEN_STATUS,
  QUIET_STATUS
};

// This is command history only; there is no physical valve-position feedback.
ExhaustState lastExhaustState = ExhaustState::QUIET;
ScreenMode screenMode = ScreenMode::HOME;

uint32_t statusScreenStartedMs = 0;
uint32_t firstClickMs = 0;
uint32_t lastAcceptedReleaseMs = 0;
uint32_t lastClockRefreshMs = 0;
bool waitingForSecondClick = false;
long reservedEncoderPosition = 0;

void drawHomeScreen();
void drawExhaustOpenScreen();
void drawExhaustQuietScreen();

void drawClock(bool force) {
  static int lastMinute = -1;
  static int lastHour = -1;

  const uint32_t now = millis();
  if (!force && now - lastClockRefreshMs < CLOCK_REFRESH_MS) return;
  lastClockRefreshMs = now;

  auto dt = M5Dial.Rtc.getDateTime();
  const int hour24 = dt.time.hours;
  const int minute = dt.time.minutes;

  if (!force && hour24 == lastHour && minute == lastMinute) return;
  lastHour = hour24;
  lastMinute = minute;

  int hour12 = hour24 % 12;
  if (hour12 == 0) hour12 = 12;
  const char* suffix = (hour24 < 12) ? "AM" : "PM";

  char timeText[8];
  snprintf(timeText, sizeof(timeText), "%d:%02d", hour12, minute);

  // The source JPEG contains a sample clock. Erase only that area, then draw
  // the current RTC time. The rest of the JPEG remains untouched.
  M5Dial.Display.fillRect(42, 190, 156, 43, COLOR_BG);

  M5Dial.Display.setTextDatum(top_center);
  M5Dial.Display.setTextFont(4);
  M5Dial.Display.setTextColor(COLOR_WHITE, COLOR_BG);
  M5Dial.Display.drawString(timeText, 111, 195);

  M5Dial.Display.setTextDatum(top_left);
  M5Dial.Display.setTextFont(2);
  M5Dial.Display.setTextColor(COLOR_RED, COLOR_BG);
  M5Dial.Display.drawString(suffix, 166, 206);
}

void drawHomeScreen() {
  screenMode = ScreenMode::HOME;
  M5Dial.Display.drawJpg(home_240_jpg, home_240_jpg_len, 0, 0);
  drawClock(true);
}

void drawExhaustOpenScreen() {
  screenMode = ScreenMode::OPEN_STATUS;
  M5Dial.Display.drawJpg(
      exhaust_open_240_jpg,
      exhaust_open_240_jpg_len,
      0,
      0);
}

void drawExhaustQuietScreen() {
  screenMode = ScreenMode::QUIET_STATUS;
  M5Dial.Display.drawJpg(
      exhaust_quiet_240_jpg,
      exhaust_quiet_240_jpg_len,
      0,
      0);
}

void pulseOutput(uint8_t pin) {
  // The required remote-button emulation pulse is intentionally blocking.
  // Keep the opposite channel explicitly idle during the pulse.
  digitalWrite(EXHAUST_OPEN_PIN, LOW);
  digitalWrite(EXHAUST_QUIET_PIN, LOW);
  digitalWrite(pin, HIGH);
  delay(OUTPUT_PULSE_MS);
  digitalWrite(pin, LOW);
}

void sendOpenCommand() {
  Serial.println("Command: OPEN (GPIO1 / white / S2)");
  pulseOutput(EXHAUST_OPEN_PIN);
  lastExhaustState = ExhaustState::OPEN;
  drawExhaustOpenScreen();
  statusScreenStartedMs = millis();
}

void sendQuietCommand() {
  Serial.println("Command: CLOSE/QUIET (GPIO2 / yellow / S1)");
  pulseOutput(EXHAUST_QUIET_PIN);
  lastExhaustState = ExhaustState::QUIET;
  drawExhaustQuietScreen();
  statusScreenStartedMs = millis();
}

void toggleExhaustFromDoubleClick() {
  if (lastExhaustState == ExhaustState::QUIET) {
    sendOpenCommand();
  } else {
    sendQuietCommand();
  }
}

void handleDialButton() {
  const uint32_t now = millis();

  // Count completed presses. M5Dial/M5Unified handles the raw button state;
  // this extra interval rejects implausibly close release events.
  if (M5Dial.BtnA.wasReleased()) {
    if (now - lastAcceptedReleaseMs < CLICK_DEBOUNCE_MS) return;
    lastAcceptedReleaseMs = now;

    if (waitingForSecondClick && now - firstClickMs <= DOUBLE_CLICK_MS) {
      waitingForSecondClick = false;
      toggleExhaustFromDoubleClick();
    } else {
      // Store the first click only. A single click never sends a command.
      waitingForSecondClick = true;
      firstClickMs = now;
    }
  }

  if (waitingForSecondClick && now - firstClickMs > DOUBLE_CLICK_MS) {
    waitingForSecondClick = false;
  }
}

void handleSerialCommands() {
  while (Serial.available() > 0) {
    const char command = static_cast<char>(Serial.read());

    if (command == 'O' || command == 'o') {
      waitingForSecondClick = false;
      sendOpenCommand();
    } else if (command == 'C' || command == 'c') {
      waitingForSecondClick = false;
      sendQuietCommand();
    }
  }
}

void setup() {
  // Safety-critical startup order: establish LOW outputs before UI/library init.
  pinMode(EXHAUST_OPEN_PIN, OUTPUT);
  pinMode(EXHAUST_QUIET_PIN, OUTPUT);
  digitalWrite(EXHAUST_OPEN_PIN, LOW);
  digitalWrite(EXHAUST_QUIET_PIN, LOW);

  Serial.begin(115200);

  auto cfg = M5.config();
  M5Dial.begin(cfg, true, false);  // Encoder enabled, RFID disabled.
  M5Dial.Display.setRotation(0);
  M5Dial.Display.setBrightness(160);
  M5Dial.Display.setTextWrap(false);

  reservedEncoderPosition = M5Dial.Encoder.read();

  Serial.println();
  Serial.println("Tacoma M5Stack Dial Controller ready.");
  Serial.println("Serial test: O/o = OPEN, C/c = CLOSE/QUIET");
  Serial.println("Dial: deliberate double press toggles last commanded state.");
  Serial.println("State is command history only; no valve-position feedback.");

  if (!M5Dial.Rtc.isEnabled()) {
    Serial.println("Warning: RTC not detected/enabled; displaying returned RTC fields.");
  }

  drawHomeScreen();
}

void loop() {
  M5Dial.update();

  handleDialButton();
  handleSerialCommands();

  // Rotary movement remains reserved for future Joying USB volume control.
  // Reading it is harmless; no media or exhaust action is performed.
  reservedEncoderPosition = M5Dial.Encoder.read();
  (void)reservedEncoderPosition;

  if (screenMode != ScreenMode::HOME &&
      millis() - statusScreenStartedMs >= STATUS_SCREEN_MS) {
    drawHomeScreen();
  }

  if (screenMode == ScreenMode::HOME) {
    drawClock(false);
  }

  delay(2);
}

Cpp
auto dt = M5Dial.Rtc.getDateTime();

Cpp
// YYYY, MM, DD, hh, mm, ss — set to the desired local time.
M5Dial.Rtc.setDateTime({{2026, 8, 18}, {19, 23, 0}});

1. Install/update the M5Stack board package in Arduino Board Manager.
2. Install the M5Dial library and all prompted dependencies.
3. Select Tools → Board → M5Stack → M5 Dial.
4. Create the main sketch as TacomaDialController.ino.
5. Add the second tab/file named exactly ui_assets.h and paste the complete downloaded header into it.
6. Confirm both tabs are visible and the .ino contains #include "ui_assets.h".
7. Connect the Dial, select its USB port, and click Verify.
8. Click Upload, then open Serial Monitor at 115200 baud.

1. Safe startup: Observe GPIO1 and GPIO2 during power-up. Both must remain LOW; neither PC817 should activate during library/display initialization.
2. Artwork: Confirm the supplied home JPEG fills the display and the live RTC clock replaces the sample clock near the bottom.
3. Serial OPEN: Send O or o. GPIO1 must go HIGH for approximately 500 ms while GPIO2 stays LOW. The OPEN JPEG then appears for about 1200 ms before returning home.
4. Serial CLOSE: Send C or c. GPIO2 must go HIGH for approximately 500 ms while GPIO1 stays LOW. The QUIET JPEG then appears for about 1200 ms before returning home.
5. Single press: Press/release the knob once and wait longer than 450 ms. Confirm no command is sent.
6. Double press: Complete two presses/releases within about 450 ms. Confirm it toggles the last-commanded state.
7. Encoder reservation: Rotate the knob and confirm it performs no action.

• ui_assets.h: No such file or directory: The header must be a second tab/file in the same Arduino sketch folder, named exactly ui_assets.h.
• JPEG does not compile: Update M5Dial, M5Unified, and M5GFX. Confirm the three arrays and three _len constants retain their generated names.
• JPEG is blank or corrupted: Re-copy the entire header; a missing byte, brace, or final length constant will corrupt the embedded data.
• Clock leaves part of the sample visible: Slight JPEG compression or artwork revisions can change the clock edges. Adjust only the fillRect(42, 190, 156, 43, COLOR_BG) rectangle while keeping it inside the bottom clock region.
• Button does not react: M5Dial.update() must remain in every loop pass. A single press intentionally does nothing.
• Wrong valve direction: Do not swap the software mapping. Verify GPIO1/white/S2 is OPEN and GPIO2/yellow/S1 is CLOSE/QUIET.
• Clock is incorrect: Set the RTC with the one-time line above or the official M5Stack RTC/NTP example.

• M5Dial Arduino setup: https://docs.m5stack.com/en/arduino/m5dial/program
• M5Dial button: https://docs.m5stack.com/en/arduino/m5dial/button
• M5Dial encoder: https://docs.m5stack.com/en/arduino/m5dial/encoder
• M5Dial RTC: https://docs.m5stack.com/en/arduino/m5dial/rtc
• M5GFX embedded image example: https://github.com/m5stack/M5GFX/blob/master/examples/Basic/drawImageData/drawImageData.ino