[OpenTRV-dev] Help getting serial connection to Radbot

Sun Feb 14 19:33:20 UTC 2021

Hi Rob,

That’s great, you’ve got very far in a very short amount of time! 

It sounds like you’re “holding” the wires on – just solder them on if you have a soldering iron around, it’s easy enough to take them back off after the operation.

I can imagine that there’s a ground potential problem and perhaps one of the devices doesn’t like the 3.0V supply. The Radbot takes very little power and I was able to simply power it from my USB-serial adapter, but that depends on the adapter of course. Alternatively, the RPi also has a 3.3V supply (and 5.0V too) and it has a serial port right next to the supply pins too, so if you have a few breadboard wires around, that would be a simple and quick alternative.

Cheers,

Christoph

From: OpenTRV-dev <opentrv-dev-bounces at lists.opentrv.org.uk> On Behalf Of Robert May
Sent: Sunday, 14 February, 2021 18:24
To: Closed list for developer discussions <opentrv-dev at lists.opentrv.org.uk>
Subject: [OpenTRV-dev] Help getting serial connection to Radbot

I've finally found time to unbox my Radbots.   The plan is to build a combined stats hub and boiler controller based on a RPi.

I've successfully compiled the code Christoph shared (https://github.com/wintersteiger/wlmcd) and used to to show the one Radbot I've powered up transmits and that I can receive the frames using a CC1101/RPi combination.  Of course the decryption fails as I've yet to set a decryption key.

I'm struggling to get a connection over the serial port to the Radbot.  I'm trying to follow the instructions shared by Tristan (https://github.com/tyrken/heatmon/wiki/Reprogramming-Radbot-TRVs) but I can't seem to get any comms over the serial port.

I've opened up my radbot to get better access to the pads.

I'm powering the Radbot from a bench power supply at 3.0V

I've got a USB serial dongle operating at 3.3V logic, grounded to the -ve supply.

I think I'm hold the rx/tx lines on the pads (tx from my dongle to rx on the radbot and rx on the dongle to tx on the Radbot), but I get nothing from 'screen' that I'm using for my terminal.

As far as I know I'm using 4800baud, 8-N-1 (screen /dev/ttyUSB0 4800), which I believ to be the expected settings?

Can anyone see anything that I'm doing wrong or give me a pointer to things that I can try. ?

Thanks,

Rob.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.opentrv.org.uk/pipermail/opentrv-dev/attachments/20210214/6f11cbd2/attachment.html>