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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.
October 10, 2009
Finished the Board
Finished building the board with all of the control relays. The obvious issue was that the microcontroller isn't supplying enough amps to power all the relays. To cheat I added a cap.
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.
