Best & Fast Prototype ($2 for 10 PCBs): https://www.jlcpcb.com Thanks to JLCPCB for supporting this video.
Learn how a PID controller for temperature works. We use a K type thermocouple and read real temperature values with the MAX6675 breakout board. SPI connected to the Arduino which will create the PID and control a MOSFET with PWM signal and the power for a DC heater.