Hi,
I started to reverse engineer the LNS protocol that is used by some Midea mini-splits (full write-up). Turns out, the data line that connects the IDU and ODU carries all kind of interesting data:
I'd like to feed this into Home Assistant, but I'd rather not deal with line voltage to capture it. My 220V units use one of the hot wires as the reference for the data line. So instead I looked at the diagnostic port on the ODU inverter board, which runs at 5V.
Unfortunately, the lines are idle when nothing's connected to the port:
[can't attach more than 1 image - i'll post this image as separate response]
Once I connect the Midea inverter tester, digital signals start appearing:
[can't attach more than 1 image - i'll post this image as separate response]
Full write-up of what I have so far: https://medium.com/@florian.mckee/reverse-engineering-mideas-odu-diagnostic-port-af603e159053
At this point I have no idea what protocol I'm dealing with, or how to get the ODU to output data without the inverter tester attached.
Any input appreciated.
