Geyserwise comms protocol?

Has anyone ever reverse engineered the comms protocol of the Geyserwise devices?

I would like to use it as a base for an automated thermostat. Hardware is great, but it would be even better if I could use it directly.

From what I can see, it seems to be a 2400 baud serial protocol (or possibly 1200 baud RZ protocol, given the odd bit patterns). But I can not see any correlations in the packets when I change temp, or press buttons…

If anybody has any previous attempts (even partial) to work from, that would be a great help!



Seems like you need a good scope with UART decode capabilities…

Seriously, I’ve been looking at a few of these and man, looks so cool, but so expensive. The Rigol entry- scope now has this standard, and the Siglent SDS1104X-E does as well (but it’s a 450USD scope). I eventually settled on a entry-level Keysight scope which has some decode capabilities… but I have not tried it yet. Would have been an awesome project to try it on :slight_smile:

I have captured the bitstream, and figured out the framing, but the data is odd. Too much repetition, and not enough variation. Almost seems like some sort of encryption/bit scrambling on top of the comms.

Will probably end up yanking their chip and putting an Arduino in…

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I would love to be able to talk to my heat pump, but I don’t have expensive scopes. It would be so much easier if companies publish their protocols.

I have looked at it as well.
An idea is to intercept the sensors before that go into the geyser wise. I am hoping for an analog signal but there is a chance that they could have used a ds18b20 sensor for the temperature. You could then use something like a Uno to transmit the data.
But so far , and Ill admit that I am also a bit lazy , I have not tested the idea.

It is a 10k NTC thermistor.

Ah analog then , any idea on the water level?

Only have a TSE and that has no water level sensor… From what I have read of the others, none actually have a water level sensor, although they do have heuristics based on heating rate to raise such errors.

Lol , sorry. I have a low pressure Solar geyser. So it has a level sensor to determine the water level to fill.