VoltLog's ESP32-Based Tasmota Floor Heating Valve Controller Plays Nicely with Home Assistant

Florin "VoltLog" C. has released another open-hardware design, this time taking an Espressif ESP32 microcontroller and building a Tasmota-compatible 10-channel valve actuator for an in-floor heating system.

"The need for such a valve actuator circuit started when I installed floor heating into my apartment," Florin explains, "and if you ask why I didn't use one of the commercially available options: I don't like them, they’re expensive and they typically only work with their closed source ecosystem, I wanted something that runs open-source so I can control and customize various aspects."

The solution: A custom board built around an Espressif ESP32 microcontroller running the Tasmota firmware — meaning it's ready for integration into the Home Assistant smart home platform.

"I have a total of 9 circuits and these circuits have different lengths and the rooms have different sizes, so putting the same volume of water through all circuits is going to result in uneven heating," Florin writes of the drawbacks of an off-the-shelf alternative.

"This issue can be mitigated by tuning the individual flow valves on the intake of each circuit but that setting seems to vary with the pressure it gets from the pump and doesn’t allow a fine granular control over the temperature of that room which is what I want to achieve."

Florin has published design files and firmware for the board on GitHub under the reciprocal GNU General Public License 3, and has also announced plans to sell pre-built versions on Tindie — but had not yet listed them for sale at the time of writing. Those looking to use the board, though, are advised to flash first-revision hardware with Tasmota 9.5.0 at the latest — owing to issues with detection of external PSRAM in later versions.