It’s slow, and I hope I’m not jinxing myself by saying it, but I think there’s some progress.
The ethernet port seems to be working(*). The temperature variances are annoying but I think I’ve found ways to live with it. Last night I added all the buttons and switches. All that remains now is to build the circuit board that will house the power regulator and the interface to the HVAC lines.
I had been worried about how it will all look – especially with the Chronodot RTC/temp sensor being not only external, but standing off about an inch. I was worried also about mounting buttons and switches. Would I do a good job? Would they look ok? Would it look like a 3rd grade science fair reject?
In a moment of zen, I found a peaceful answer to all these concerns. My thermostat is going to look a little bit like mad science. People are going to be wary when they see it. People are going to be afraid to touch it. And that is the way it is meant to be.
The grey wire coming out the bottom is the ethernet cable. The blue board & black cable on the left side is temporary, it is the USB/serial connection that I’m using for debugging, and temporarily providing power to run the thermostat. Down below to the right of the ethernet port, is where I’ll be building the power & HVAC interface circuitry.
* There is one ongoing sporadic problem with the ethernet port. Sometimes after a power loss, it hangs on initialization. I suspect I know what the problem is, and how to remedy it. For now, it just means occasionally having to hit a reset button after power-up.
I’ll include some pics of the guts in my next update post.