I've had it running for weeks now and it seems to be working fine in my test mode. Test mode is to sample humidity/temp, handle power failures, sensor failure, send email when this happens, and log data to a SQL database. The temperature is just the temp sensor sitting above a light bulb that is controlled by the controller. This has been running for about a month without issue so it is now time to make the next step. I'm going to now actually control the fridge and humidifier instead of just driving a light bulb.
Does anyone know the minimum safe cycle time for a fridge? I.E. how quickly can I turn it on/off without damaging the compressor? I looked around on line and for home AC compressors it is ~3 times per hour. Not sure if that holds for fridge or not. Hopefully someone here knows the answer. Or for those of you that have done this already, what do you see with your chamber?
Next I need to pretty up the web interface that allows me to control the unit, plot the data and everything via php javascript. Anyone out there interested in helping with this aspect? I've got the c++ code done for the pi, and while the javascript I put together is functional, it is quite ugly

I'll post later on how it actually works to control the fridge.
thanks,
dave
P.S. - this will be a slow process for me as real life, work kids interfere with my fun, but I'll keep the thread updated.