Note: Work in progress
Temperature controller for waterbed heater.
- Temperature controller on ATMega328P (Arduino)
- Dallas D18B20 Temperature sensors
- Brett Beauregard's PID Controller Library
- Output modulation using solid state relay
- Remote accessible using ESP8266 / ESPLink
- Python script to connect the controller to MQTT
- OpenHAB integration (via MQTT)
To Do:
- Fail-Safe relay in series with SSR (as failure mode is typically to fail short)
- Bypass relay in parallel with SSR to minimise dissipation if maximum output is required for extend time (eg. heating up cold bed)
- Add Display/UI
The original waterbed controller was properly maintaining a constant temperature. Inspection of thermostat's internals showed that the controller was purely electromechanical, so no surprise no accurate & stable regulation could be obtained.
Original Controller:
Pin Assignment Reset - gpio3/RX0 ISP/Flash - gpio1/TX0 TX Enable - disabled Conn LED - gpio0 Serial LED - gpio14 UART Pins - swapped RX Pull-up - disabled
Serial Baud 57600