This is the first set-up of the electronics to test the code I’ve written.
The blue usb cable connects the Arduino Nano to the computer to display serial data. On the breadboard is a 5v power supply and 2x DHT22 sensors. These give temperature and humidity readings. Also there is a 2 relay board and a servo. The programme reads the temperature and operates a relay that powers the heater. The second relay powers the vent fans whilst the servo opens the vents. Venting is done periodically for now but could be used to react to and moderate humidity.