The coffee maker hotplate has a significant delay which causes control problems....

By the time the sensor sees a temperature change, enough energy has been put into the plate that it shoots up to a very high temperature. The process does not seem to stabilize with just PID control.

To correct this, we edited the PID algorithm. Now the hotplate is pulsed on between 0 and 1 seconds every 10 seconds according to the PID algorithm.

More details coming....