# arduino_gauge_controller

A dedicated gauge controller for Arduinos.

## Overview

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

## VFD Support

The integrated gauge controller now includes a 4-digit VFD with:

- 4 alphanumeric digits
- decimal point indicator
- alarm bell indicator

On the merged Arduino firmware, the HV5812 control pins are:

- `D46` -> `DATA`
- `D47` -> `CLOCK`
- `D48` -> `STROBE`
- `D49` -> `BLANK/OE`

The standalone VFD sketch used `D51/D52/D53/D49`, but `51/52/53` conflict with the gauge stepper pins in the integrated controller.

## Arduino Serial Commands

The merged Arduino firmware accepts:

- `VFD`
  clears the display and turns off decimal point and alarm bell
- `VFD 1234`
- `VFD 0123`
- `VFD DEAD`
- `VFD 8888.`
- `VFD BEEF!`
- `VFD 12AF.!`

Rules:

- up to 4 characters are displayed
- valid characters are `0-9`, `A-F`, and `-`
- `.` enables the decimal point
- `!` enables the alarm bell
- shorter values are right-aligned
- leading zeroes are preserved if they are part of the input

## Home Assistant Entities

The MQTT bridge publishes Home Assistant discovery entities for the VFD:

- `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:

- leading zeroes are preserved
- hexadecimal values like `DEAD` or `BEEF` work
- clearing the display is possible with an empty value

## MQTT Topics

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.`.