My HGI80 equivalent Domoticz setup without HGI80

[DanD]

Yes, it is a bit pot-luck with the low-cost CC1101 devices. I was lucky with my first purchase which was a £2 device purchased directly via an Ebay seller in China and an 868MHz device turned up. I decided to purchase my last one from a UK seller which cost £12 as I wanted one with header pins and antenna with socket to help with further testing.

[thigger]

Well, I have an 868Mhz setup now (with irritating slightly-smaller header spacing that meant I had to alternate pins on each side of the board!). Unfortunately this board doesn't support the SMA connector and has its own little antenna, but the range seems to be much improved and I'm reliably getting messages from all over the house.

My questions now:

• Is there any way to "inject" commands safely? I'm using evohome-Listener to connect to OpenHAB via MQTT. I've always wanted some form of local control, but equally don't want to end up writing my own software to replace the whole controller!
• How does heat demand work? I have two BDR91s - CH and DHW with no direct boiler control (boiler is fired from the valve microswitches). I frequently see messages suggesting the relay heat demand is 56%, but the actuator is off so the boiler isn't firing. Is the CH relay doing some (very slow) PWM or similar? This even seems to happen if I tell the controller there's an OpenTherm relay (without anything bound) - I just start to get boiler demand messages in the same way - but the actuator turning on and off seems to be independent.

Edit: done a bit of reading and it sounds like this is expected behaviour - TPI at 6 cycles/min with no minimum on-time in the case of my two-relay system. I'm hoping it behaves slightly differently when it thinks there's an OpenTherm boiler connected as the water temperature will vary (which is what I'm expecting to do with my reset-sensor hack)

[dty]

Yes, the heat demand (and config params) are sent to the BDR, and it takes care of turning itself on and off according to the required demand.

You can inject commands, yes. I'm not sure which firmware you're running. If it's mine (or a derivative), this *used* to work. I've not tried it for a long time though, but I see no reason why it shouldn't. Domoticz uses this feature to be able to update the controller mode (away, day off, etc.), the setpoints, etc.

[DanD]

Is there any way to "inject" commands safely? I'm using evohome-Listener to connect to OpenHAB via MQTT. I've always wanted some form of local control, but equally don't want to end up writing my own software to replace the whole controller!

I play around a lot with injecting commands into my Evohome systems via Domoticz and also directly as part of my of my ongoing work on the Domoticz code, fixing bugs and adding additional functionality. The only time I've ever been able to temporarily mess up my system is during some testing of experimental schedule upload/download functionality which caused the controller to lock-up. This was fixed simply by removing the batteries and it restarted with no problems or loss of information, so I'm pretty confident that you won't mess things up by injecting commands. Unfortunately though, I don't have any simple suggestions for how to directly inject your own messages. I sometimes just send an appropriately structured message via a serial port client e.g. PuTTY etc, but there is very little publicly available information on the message structure etc. so it's pretty much trial and error.

Dan

[MaikelK]

Well, I have an 868Mhz setup now (with irritating slightly-smaller header spacing that meant I had to alternate pins on each side of the board!). Unfortunately this board doesn't support the SMA connector and has its own little antenna, but the range seems to be much improved and I'm reliably getting messages from all over the house.

Hi thigger,

I also want to use ESP8266 and C1101 to sniff the data from the Evohome.
Which C1101 module did you order, do you have a link to it?

Could you discribe how you connect one another and which software you uploaded and how you did it.
Im able to upload ESPeasy for example but that's about it... Trying to figure out compiling stuff etc but dont find that to easy.

[DanD]

Hi,

I've not used the ESP8266 with the CC1101, but here's a link to someone's set-up which gives a helpful pin-out for the connections required:
http://www.bastelbudenbuben.de/2017/...ode-betreiben/

You'll see from the pic that they used direct soldered wires to connect the two boards which is a simple solution and avoids the problem of sourcing headers/converters for the different pin spacings. I prefer to use use headers and sockets to allow easy re-use and troubleshooting, but it can be a real pain to track down the necessary parts.

My understanding of thigger's set-up is that they modified petep's firmware to work on the ESP8266 and then they used one of the Evohome listener programs, their post mentions "smar's python listener".

I've bought a few different types of CC1101 modules, but here's the one that I would recommend due to pin header and antenna and they seem to work OK at 868Mhz (I've not used this seller though). It's a different layout from the example above, but the pin-out is labelled on the board header:

[URL="https://www.ebay.co.uk/itm/CC1101-Wireless-RF-Transceiver-315-433-868-915MHZ-SMA-Antenna-Module-ZX/202683412823[/URL]

Regards,

Dan

[MaikelK]

Hi,

I've bought a few different types of CC1101 modules, but here's the one that I would recommend due to pin header and antenna and they seem to work OK at 868Mhz (I've not used this seller though). It's a different layout from the example above, but the pin-out is labelled on the board header:

[URL="https://www.ebay.co.uk/itm/CC1101-Wireless-RF-Transceiver-315-433-868-915MHZ-SMA-Antenna-Module-ZX/202683412823[/URL]

Regards,

Dan

How do you put this unit in 868mhz mode then?

I saw those to and like the fact of a proper antenne.

[DanD]

The center frequency is one of the many CC1101 parameters that are dynamically configurable via the connected MCU. A simplified summary is that the MCU sends these configuration parameters to the CC1101 at startup and these configure the modem, packet handler and data buffer.

[MaikelK]

Would you have an example of such a script maybe?

I didnt order the board with the wire antenna yet as i like the one you send more for having a real antenna.

[DanD]

Here's the link to PetePs firmware https://github.com/ghoti57/evofw2/tree/fifo. CC1101.c contains all the CC1101 configuration stuff. I can't really help with how to port this to an ESP8266 though as all my work has been on various arduino clones.