Originally Posted by GriFF3n
The arduino will be connected to a temperature probe. The program will monitor the probe and send a control to turn off the elements once the desired temperature is reached. Thats the function of this project. Adding a PID controller is a great idea, I just don't know how to do it.
I think I get it, however your using sledge hammer to nail in decking, while it'll get the job done, its the expensive and under-utilized way of doing things.
Just so I have it clear, your using the ardino to set a temperature at which to turn a single relay off while keeping the second heating element on? I believe you'd be much more satisfied with using a PID control set up.
Pulse Width Modulation is a technique where by varying the % you have the heating element on you can control how much heat actually goes into the kettle. PID is a control algorithm used to adjust how much heat to put in based on the Temperature probe.
While you can go out and buy a dedicated PID controller and it may be the easier option in this case, you can program the arduino to act just like that PID controller.