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..