Gateway shield works -also on wemos esp8266 !
For OpenTherm Gateway Arduino Shield
With some support of Jiri I managed to get the gateway up-and-running on an esp8266 wemos mini pro d1!
The advantage of the wemos in comparison with arduino is its low cost, size, speed, power usage and standard wifi functionality including an option to add an external antenna. ( e.g. https://www.hobbyelectronica.nl/product/wemos-d1-mini-pro/ )
To make this work I ordered a arduino proto board to click in the gateway shield and solder it to the wemos. Some small adaptions on the shield make it work on the 3.3V platform of the esp8266.
I managed to see every command the thermostat sends to the boiler and I can capture the feedback of the boiler.
My next steps are
- add display to wemos to see current state of the boiler, thermostat, and show connections are good.
- use the wifi link the data to my sql database running on my NAS (I know this works already)
- readout 2nd thermostat (on/off) via input and enable boiler via the opentherm
- get everything nicely in a box e.g. add 24V supply and nicely enclose it
- build a web-access to from outside enable boiler or readout temperature
- experiment further with opentherm commands
* e.g. make sure the thermostat always has the right date/time (via internet time server)
* add external temperature sensor
etc. etc.
If more people have interest, maybe Jiri will develop a shield that fits standard for Wemos ?
Anyhow this is a good product with good support and can be fun and useful to save energy costs!
