Relay control
General description
The arduino receives information from the heat sensor and saves it's starting temperature in Celsius and allows electricity to go through the relay, in this case this allows an element heat up water, it does this for temperature*1000 milliseconds. If the sensor detects a temperature higher than it's starting temperature it activates the relay that extra amount.
Components
For this project you will need: An Arduino, A relay, A DHT temperature sensor, A breadboard for additional connections, Electricity, Something for the relay to control
Opiration
Simply upload the code to the arduino and make sure everything is connected properly.