Flo's Espressif ESP32-S3-Based Under-Floor Heating Controller Aims to Smarten Up Your Toasty Feet

With six AC inputs and outputs, this multi-channel controller can work independently or through connectivity to Home Assistant and the like.

Pseudonymous maker "Flo" has released the design files and source code for an Espressif ESP32-S3 under-floor heating controller, designed for retrofitting to existing heating systems and delivering six inputs and outputs.

"[This is] a six-ch[annel] 230V mains underfloor heater valve controller with six mains inputs, based on an [Espressif] ESP32-S3," Flo explains of the compact board. "[It has] six AC inputs for reading the wall thermostats as fallback (no Wi-Fi [or] Home Assistant dies) [and] six AC outputs using Optotriacs (max. 1.2A/channel)."

The board is driven by an Espressif ESP32-S3 microcontroller, giving it easy connectivity to Wi-Fi and from there to smart home systems like Home Assistant, and sits within a 3D-printed case with its connections exposed as screw terminals on the outside. There are UART and I2C buses for future expansion, Flo explains, and a OneWire bus aimed at Analog Devices DS18S20 for reading pipe or room temperatures.

The board is designed to be powered from a 3.3V DC supply, Flo explains, and delivers an idle power draw of just 0.4W. It's also built to be easy to add to existing under-floor heating systems β€” though, for those who prefer a DIY approach to off-the-shelf hardware, there's nothing to stop it being used on new-build installations too.

The project is documented, with schematics and board layout files, on Hackaday.io; source code had not been published at the time of writing.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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