Ah, homebrew! I use Johnson Controls A419-ABC digital temp controls for my kegerator and my laagering cooler (both old chest freezers). It costs about $50 from a local HVAC supplier (G.A. Larson, who has branches around the country). It runs on and switches 120V, has offset, anti-short-cycle delay, and programmable dead-band. The control can be setup to turn on or off on temperature rise. I can hold temp to within a degree or so after fine tuning the controller. Now go have a beer..... Edward Gisske, P.E. Gisske Engineering 608-523-1900 gisske@offex.com ----- Original Message ----- From: "Eisermann, Phil [Ridg/CO]" To: Sent: Friday, January 16, 2004 8:47 AM Subject: Re: [EE:] About test boxes (hot and cold) pic microcontroller discussion list wrote: > It seems that I'll start my tests with a no-frost deep-freezer that my > fridge has (~180C) and for the heat, I'll use my wifes blow > dryer. And go > from there... > I'll offer another suggestion. The home brewing industry has these little temperature controllers for around $150 or so. You turn your freezer to the coldest temperature, but the freezer is plugged into the temperature controller. The controller turns the freezer on or off as required. It can be set for heating or cooling IIRC. So, there's the cooling side already taken care of. For heating, you could dismantle a toaster oven and mount the coils on a suitable bracket to the inside of the freezer so the plastic doesn't melt. Unplug the freezer, and plug in the oven coils instead. It should also be simple to build a PIC circuit that could control both heating/cooling at the same time; using ready-made components would allow you to quickly test the feasability of this concept. Phil Eisermann Electronics Engineer The Ridge Tool Company (440)329-4680 -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu