Friday, September 30, 2011

Opentherm JeeNode shield PCB

Progress has been slow, but steady, in the opentherm front!

As I mentioned before, JCS is helping me out with the PCB part, and he has produced a nice PCB in the form of a shield for a JeeNode, which should be able to connect to the boiler! I leave to him to explain how he does his magic...

I have drilled the holes today, big victory for me, and now I just have to populate the board, cut it to the proper size, and develop the software.

I also still need to properly dimension the resistor at the detector optocoupler before I solder the whole thing on the PCB.

In the picture some resistors are still missing, but I just wanted to make this public! The designs and software will come soon!

i just realised that I should have included a couple of LEDs on the board to display status, but it can still be added in a later revision :)


pieterjm said...

Very good work, and i'm interested integrating the circuit in my own home automation environment.

Could you please send me an email? I could not find your contact details on your website:

fmartens said...


I already have a PCB for the Arduino that I need to test soon. I need to write some code for it. I will release the eagle files as soon as I have found a host to host it.

Are you going to release your design also and is JCW going to create and sell the PCB in the JeeNode store?

How is your design doing at the moment, are you satisfied with the results?

Your blog is very interesting and I will return more often :-)

Alex said...

I will release my design...I hope :) the code is available in github (see elsewhere in the blog).

As for JCW creating a selling the PCBs I don't know...I guess he could improve them a lot. The guy helping me is JCS, not JCW, that might be confusing :)

My design is working fine at the moment - communication to the boiler is working fine, and I am very satisfied. I am about to send the PCB to be manufactured professionally, and then get everything in an enclosure and set it to work.

Do keep us updated of your progress!

fmartens said...


Is your design also usable as monitor? Can i 'insert' it into my existing configuration between the boiler and the Thermostat?


Alex said...


I don't think it can work out of the box as a could monitor the transmission from the boiler to the thermostat using only the optocoupler section , as that is a current transmission, but for the communication from the thermostat to the boiler, which is a voltage transmission, you would have to adapt it to measure the voltage across the two wires. I don't know how difficult it would be to so that...

There is an opentherm monitor design available in the internet, from Elektuur, and a gateway using a pic, not a atmega:

Alex said...

IThere is also this Arduino based monitor, maybe this is what you need if you only know Arduino (like me :):

fmartens said...

I already build the Arduino monitor, I have the eagle files available :-) I was curious if your design did work as a monitor also because I like the jeenode form factor :-)

My ultimate goal is to monitor my Remeha via OpenTherm and the RECOM interface :-)