Smart Home · IoT · Wireless Automation · STM32 & ESP-12
WiFi Underfloor Heating Controller
A flush-mount IoT heating controller designed to fit inside standard electrical wall junction boxes with open TCP/IP API for smart home integration.
Unable to find commercial floor heating controllers with open APIs and zero cloud lock-in for home automation, I engineered this custom hardware unit. Driven by an ARM Cortex-M STM32F103 microcontroller teamed with an ESP-12 WiFi transceiver module. Upon boot, it connects to local WiFi and opens a listening TCP/IP socket for instantaneous temperature polling, state changes, and remote relay switching. Firmware updates are supported over-the-air (OTA).
Technical Specifications:
- Input supply voltage: 230 V AC (onboard isolated switching AC/DC power supply)
- Relay contact rating: 10 A resistive load
- Floor temperature sensor: NTC thermistor
- Operation modes: Autonomous thermostat loop or remote centralized supervision
- Configurable hysteresis deadband for energy-efficient temperature regulation
- Open TCP/IP protocol for seamless integration into home automation controllers
- Safety timeout: automated shutdown if target threshold is not reached within guard time
- Wireless OTA firmware updating
Hardware Assembly & Photos
