A thermostat accessory for remotely controlling central heating. This is a Apple HomeKit thermostat with SSD1306 display and three buttons, with which you can adjust the temperature up / down. The third button is to change the mode and reset the homeKit configuration. This thermostat communicates with a relay to control the heater.
It uses a nodemcu, a DHT22 sensor, a SSD1306 OLED display and a KY-019 relay.