Quote Originally Posted by nomad View Post
Can anyone give me the code and schematics for a full refrigerator controller. URGENT my food is spoiling! lol ok seriously now. has anyone seen a project such as this anywhere? we have a ge fridge that the controller keeps going out, and at 90 each, i'm going to try my hand at making my own. we have another fridge, so time isn't a problem. dont think it should be very difficult to make one that lets it cool, times a de frost cycle, and while i'm at it display temps etc on an lcd. just looking for suggestions before i start. like what would be an appropriate temp sensor for freezer? for fridge part? anyone know of an ice/frost detector/sensor? this should be a fun one for me. and i'll be sure to post code and schematics once i get it all done. these ge's are notorious for flaky controllers.
Do you happen to know what in particular keeps going out on them?

As far as the project goes...PIC (obviously ), DS18B20, well isolated PSU for the PIC/DS18B20, generic 16x2 LCD, opto-isolated relays for the compressor.

Frost detector? Shine an LED onto a piece of glass, photodetector on the other side. Glass frosts up, kills the light from the LED, bam, instant frost detector. I think. I've never tried it, but it sounds good to me.

And as far as I know (I just had my fridge worked on a couple months ago and I'm just going off what the guy told me), what a person needs to sense is the fridge temp, not the freezer temp.
The freezer gets as cold as it needs to be because the cold air gets there first, then it vents that cold air down into the fridge, usually somewhere around the front of the fridge, sometimes in the back. So, theoretically, the fridge could be 34, the freezer could be 33, or the freezer could be 0. Sometimes there's a damper that'll keep cold air from the freezer from falling into the fridge. Depends on the model I suppose.