https://www.youtube.com/watch?v=NDXUHImA3Xc
To stop the Hot End Cooling fan from running all the time, Chuck created a DIY Temperature Controlled Cooling Fan for his Creality Ender 3 Pro. The design is a simple transistor circuit without any code or firmware required. The fan comes on at 60c and off at 50c. It helps to make the fan last longer and not continue to run after the printer has stopped printing.
Chuck uses the Bantam Tools PCB milling machine to make a custom circuit board for the design and shows you all the steps to installing it on the Creality Ender 3 Pro.
