This arduino sketch implements a basic home thermostat controller which connects to the wireless MySensors network for remote control and monitoring.

• Arduino Mega2560
• BMP180 Berometric pressure + Temperature sensor
• DHT22 Temperature + Humidity sensor
• NRF20L01+ radio module for Remote Control & Monitoring.
• Generic 4 channel relay module
• Generic 16x2 LCD + Keypad shield

• MySensors
• Adafruit Unified Sensor Driver
• Adafruit_BMP085_U
• Adafruit_DHT_Unified

Similar to the most basic general-purpose home thermostats, this can control heating, cooling, and fan operation. The main features of the MySensors API for S_HVAC (Thermostat/HVAC device) are also implemented.

Standard HVAC control features:

• Min and Max runtime for each relay
• Delayed fan shutoff
• Mutual exclusion between heat and cool relays
• Enforced min and max temperature ranges
• Prevents overlap between heat and cool ranges

Remote control:

• Temperature range and operation mode can be controlled via the MySensors gateway.

Monitoring:

• Transmits Temperature, Humidity and Barometric Pressure to the MySensors gateway.

Other stuff worth mentioning:

• Averages reading from two temperature sensors
• Modes: Off, Fan, Heat, Cool, Auto
• Separate, configurable heat and cool tolerances control how far temperature is allowed to vary from the setpoint.
• When set to auto there are two setpoints
• low-temperature limit triggers heating
• high-temperature limit triggers cooling.