Electronics > Projects, Designs, and Technical Stuff
Reverse Engineering central heating wireless thermostat - help needed!
QuitButton:
I've been pointed to the pose by philpem as I was helping a friend a while back to get some of the MT10RF protocol worked out - we didn't get too far and then unfortunately life got in the way...
However, I've just spent a few hours over the last couple of days coming up with a bit of rough STM32 arduino code that creates a bitstream array that matches the protocol you've posted and it matches a few sample captures I've compared it against. I'll tidy it up a bit and post it somewhere as it could be useful for someone.
The plan was to use a RFM22B to transmit the code (I can't see as it can be transmitted using the RFM22b's internal packet handler, so I coded it to use a timer)...but I'll admit I'm totally baffled by the RFM22B's datasheet and so far I've have little luck making head nor tail of any example code to get something as simple as the right frequency and offset. :-//
Does anyone know of a simple to use Arduino friendly TX module for 868MHz?
QuitButton:
--- Quote from: philpem on June 03, 2020, 02:43:53 pm ---...
Pc: ID1 in a pairing block, otherwise a sequence number: 0x0A, 0x14, 0x28, 0x32 (then wraps round to 0x0A)
--- End quote ---
I'm seeing something more than just a basic sequence number. The one I'm playing with now for an "on" command sends 3 x "on" with 0x28, a pause, one "on" with 0x32, then back to 0x28 while heating needs to be on. For the off sequence it sends 3 x "off" with 0x14, a pause, "off" with "0x0A", then "off" with 0x14 etc.
--- Quote from: philpem on June 03, 2020, 02:43:53 pm ---
It's 868MHz FSK (specifically 868.29MHz), 4kHz deviation.
--- End quote ---
I don't know much about RF but looking at the signal using SDRsharp and a RTLSDR I'm seeing near 100k between upper and lower peaks. Surely that can't be right can it?
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