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Old 01-20-16, 10:51 PM   #10
bbro62
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Quote:
Originally Posted by jeff5may View Post
From where2's response, it sounds like the control panel is just a glorified keypad. Are you sure there are two-way comms going on (duplex)? If not, the main unit may only listen to the control panel when it wants to. Kind of like a power window module in a car, the control panel can squawk all day and the main unit might not listen. Pushing a "close window" button after the window is closed, for example.
I don't know about 2-way communication but I do think it is more like a glorified (and pretty ugly) keypad. From what I can tell, the wall controller is a transmitter and the control board on the HRV the receiver. But the manual does say that the 20 minute timer control is handled by the wall controller but the timer switches are wired to the main control board. So there must be some communication from the control board to wall control.

The brains of the control board is a MC68HC705P6ACP microcontroller. There is a sticker over the chip on the wall controller board but I suspect it is the same. There are only 5 possible control commands so I was wondering if a process similar to this tutorial (Learn to Translate IR Codes and Retransmit Using Arduino | Hackaday) would work to capture the control signals and program a microcontroller to reproduce them. Or is there an easier way?

Like you said in your earlier post, I would prefer to take over control by replacing it with an Arduino or similar. Not only could I take an ugly control box off the wall, but it would open possibilities to do other things like use motion sensors to trigger the HRV whenever someone enters a bathroom. Or not run when the temperature outdoors fall below some threshold. In other words, make it smart.

Also from your earlier post, you are right about it being generic parts. As far as I can tell, this is actually a Venmar unit with a Carrier sticker. And it looks like all HRV's sold in the US and Canada use variants of the same controllers manufactured in Canada.
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