DCBuddy features an ESP32-C3 microcontroller, and is both Open Source Hardware and runs on Open Source firmware.

Information is availble at the GitHub repository:

https://github.com/blueacro/reefvolt-dcbuddy

Automatic firmware via ESP-Web-Tools is available at:

https://blueacro.github.io/reefvolt-dcbuddy/

Note you will need to use Google Chrome.