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HVAC Thermostat Dev Blog
January 6, 2010
Darlington Array Issue
So I've created most of the HVAC Controller and I am using a Darlington Array to switch some relays. It took me a while to figure it out but I finaly realized that the Darlington Array switches to ground. I may have the IC of the array power inversely which may be causing this but once I realized that the relays needed a positive feed and then go to the Array, everything worked.
September 19, 2009
Start of the project
Well, I broke the HVAC controller board in the furnace because I was trying to get the humidifier to work whenever the fan was on. So, the board is now toast. I started work on the components, it's a fairly simple design in that there is a microcontroller controlling relays. That's pretty much it.