Geyserwise: Wire protocol between display panel and control box

R

regstraton

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I have a Geyserwise hot water collector system: https://www.geyserwise.com/

From an IoT perspective I would like have access to the information that is shown on the display, such as the temperature, when the pump is running, etc. It would be great to have these values published on MQTT. So listening in on the wire between the display panel and the control box seems like a good idea.

To do this I first need to know what wire specification and messaging protocol is used. The cable contains three cores: GND, ~+12V DC and a data line. So it must be some sort of one wire protocol, but the rest I still need to figure out. I'm about to start reverse engineering it but if someone already knows that would be a great help.

Many thanks,
Reg
 
Alternatively rip out all of the geyser wise guys and replace with a 2 Shelly's.

Basically need to measure the temp in geyser and solar collector which should be simple enough with a node MCU/rpi

Use one of the relays to on the node MCU to switch the pump based on the temp difference and 1 relay to switch the geyser element using a contactor?
 
Also following. You mean to say the "local.hero" geyserwise is just chinese junk :) who would have guessed!

If it is the same as the link, then the comms is ZigBee, the wire is just for power?

I guess you could connect up an oscilloscope and see what is coming?
 
richjdavies said:
Also following. You mean to say the "local.hero" geyserwise is just chinese junk :) who would have guessed!

If it is the same as the link, then the comms is ZigBee, the wire is just for power?

I guess you could connect up an oscilloscope and see what is coming?
Click to expand...
How many cables in the wire going to the controller?
 
Last edited:
richjdavies said:
Also following. You mean to say the "local.hero" geyserwise is just chinese junk :) who would have guessed!

If it is the same as the link, then the comms is ZigBee, the wire is just for power?

I guess you could connect up an oscilloscope and see what is coming?
Click to expand...
I think this is a ZigBee replacement for the original unit
 
richjdavies said:
Does this give you a clue. Is it just temperature? One wire temp is likely a pretty standard one or two chips

etd.cput.ac.za › handlePDF
Web results
Effective geyser management through intelligent hot water usage profiling.pdf
Click to expand...
With temp sensors there's a few types and most can be interpreted with the right code
 
That's interesting @Marct27. It would be really neat if it has Zigbee capability. Would be good to get some level of confidence before buying a bridge.

@alqassam the cable has three cores: GND, ~+12V DC and what might be a data line.
 
Following - my new place has this exactly

regstraton said:
I have a Geyserwise hot water collector system: https://www.geyserwise.com/

From an IoT perspective I would like have access to the information that is shown on the display, such as the temperature, when the pump is running, etc. It would be great to have these values published on MQTT. So listening in on the wire between the display panel and the control box seems like a good idea.

To do this I first need to know what wire specification and messaging protocol is used. The cable contains three cores: GND, ~+12V DC and a data line. So it must be some sort of one wire protocol, but the rest I still need to figure out. I'm about to start reverse engineering it but if someone already knows that would be a great help.

Many thanks,
Reg
Click to expand...
 
regstraton said:
That's interesting @Marct27. It would be really neat if it has Zigbee capability. Would be good to get some level of confidence before buying a bridge.

@alqassam the cable has three cores: GND, ~+12V DC and what might be a data line.
Click to expand...
Looks like there are several models, this one does not seem to have any antenna or additional boards on it unfortunatley.
 
I've decoded the 1 wire signal. Its essentially just duty cycle encoded (short 400us pulse = 0, 800-1400us pulse = 1). 32bits transmitted at a time. LSB first. Temperature packets are 0x1800ZZ00, where ZZ = (temperature in degrees + 15). Another packet has two bits to indicate heater element state.
 
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cvschalk said:
I've decoded the 1 wire signal. Its essentially just duty cycle encoded (short 400us pulse = 0, 800-1400us pulse = 1). 32bits transmitted at a time. LSB first. Temperature packets are 0x1800ZZ00, where ZZ = (temperature in degrees + 15). Another packet has two bits to indicate heater element state.
Click to expand...
Nice! Is there a message for the buttons in the other direction?
 
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