HeidelBridge

HeidelBridge is a firmware for ESP32 microcontrollers. It allows you to bring your Heidelberg wallbox into your WiFi network. This is done by turning your wallbox into a Daheimladen compatible device. This way the wallbox can easily be integrated into home energy management systems like evcc.

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Required Hardware

You only need two components for this project: an ESP32 microcontroller and a MAX485 module. Both are available in large quantities and at reasonable prices on the Internet. You will also need a breadboard and a few jumper wires. All in all, it shouldn't cost you more than 10€.

Parts list:

• ESP32 microcontroller*
• MAX485 breakout board
• 6 jumper wires
• A breadboard

This should be enough for quickly putting together a fully functioning prototype. Of course a well designed PCB would be much nicer, but this is still work in progress. Once the design is ready, the schematics will be available right here.

* This project is currently based on the classic ESP32. It has not been built/tested for newer models, like the S2 and C6.

Getting Started

To get your very own HeidelBridge up and running follow these guides:

• Step 1: Programming the ESP32
• Step 2: Hardware Setup

Keeping Your HeidelBridge Up-To-Date

Heidelbridge supports OTA (Over The Air) updates. That means that you can update the device firmware via WiFi without physical access to the device. This process is described here: updating your HeidelBridge.

Using HeidelBridge With evcc

Adding your HeidelBridge to evcc is very straight forward. See these instructions for details.

Using HeidelBridge With Home Assistant

HeidelBridge can easily be integrated into Home Assistant. Check out this guide to get started.

GUI Example:

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Available APIs

The HeidelBridge offers a MQTT API and a REST API. You can find more details about both APIs in the HeidelBridge API Reference.

Web Endpoints

The following web endpoints are currently served by HeidelBridge:

URL	Function
{ip}	Configuration web interface
{ip}/update	OTA update web interface

Contribution

❤️ Help is welcome! Do you own a Heidelberg Energy Control wallbox? Are you a Modbus expert? Do you have ideas for improvements? Did you find a bug? Feel free to review the code, create pull requests, open issues or contact me directly.

Used Assets and Libraries

The following assets and libraries are used by this project:

• Blueberry logo
• eModbus Arduino library
• Async TCP Arduino library
• ESP Async Webserver Arduino library
• Websockets Arduino library
• Async MQTT Client
• Daheimladen Modbus API