openThermostatShield

The openThermostatShield is an Arduino shield that makes it possible to connect an Arduino to the central heating boiler and control it.

How to build one yourself

What you need

• Soldering iron and solder

Bill of Materials

• See openThermostatShield_BOM.xls

Remarks

• R6: Short
• DS18B20: Right-Bottom pin needs to be connected with 3v3 (one but last pin on top header)
• Display: Place header on the top
• Q1 and R4 are optional (instead of relay); JP2 and JP3 as well

Arduino and firmware setup

Pin reference

• Buttons: 6, 7
• DS18B20 (temp): 5
• Relay/LED: 3
• Display: CS = 9, DC = 8 (and RST = RST)
• RFM12B wireless module: CS = 10

Libraries

• Button, LED and relay: See example “Digital” included in the Arduino IDE
• DS18B20
  • https://github.com/milesburton/Arduino-Temperature-Control-Library/
  • http://playground.arduino.cc/Learning/OneWire
• Display: https://github.com/adafruit/Adafruit-ST7735-Library