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There is a direct connection from the OTGW to a Raspberry Pi possible with a lot less components, described in this post.

Has anybody tested this or can this be used in the current PCB with some breadboard or something?

I want to start using the OpenTherm Gateway and strap it on the back of a Raspberry Pi with an as simple as possible connection without using up too many USB-connections.

I didn't tested it, but why not?
OTGW uses TTL signal between PIC & MAX232, but RasPI uses 3.3V logic.
You can't connect it directly - you kill RasPi GPIO ports.
Google schematics, it should be easy enough.
There is new "MAX232" - MAX3232. It can operate at 3.3V signals, so you can connect MAX3232 to RasPi directly, and then connect MAX3232 with MAX323 in OTGW.
This should work.
Or you can take MAX232 out of OTGW (if you have it) and use something like SN74LVC1T45 - for me it's a bit more complex, then a pair of MAX's.
Sorry, don's saw the link first time... anyway.

Dear All,

I am following this project already for quite some time, and it is really interesting.
For me though, living in Amsterdam with the Boiler outside at the balcony ) it is impossible for me to connect to the RS232 port.
The only sensible way to go for me is Raspberry Pi. Of course I would like to have a mean and lean solution... less is more...
I read up and I am fully aware of the voltage problem 5V versus 3.3V (Pi). And even saw the solution @ http://www.domoticaforum.eu/viewtopic.p ... 199#p65199

Now I wondered and though, most of us would seek an energy efficinet remote controlable solution?
Could we make some PCB's which are designed with Raspberry Pi in mind? I think there would be enough animo to make 'Opentherm Gateway Pi' geared to use with a Pi.

-We could get the GUI out of the Gateway and make a webserver in the Pi, Making OTmonitor webbased.
- Easy connection of the RS232 port to GPIO
- Wireless remote management (Over Wi-Fi)
- Greatly extend the community and development
- Pi could be turned into a all round Domotica Hub

What do you guys think? A poll to see the animo and than have some PCB's fabricated?

menno2000 wrote:I am following this project already for quite some time, and it is really interesting.
For me though, living in Amsterdam with the Boiler outside at the balcony ) it is impossible for me to connect to the RS232 port.

That's a strange setup. But the gateway doesn't have to be located near the boiler. I assume your thermostat is inside. You can connect the gateway there, or anywhere in between.

Unfortunately there is no way to get in between the two.
My thermostat is placed on the wall and its two wires go straight to the outer wall of the balcony.
Placing a Raspberry Pi is my only way out But I would like to see a more native GPIO- RS232 first and a webinterface

Ill follow the projoect carefully!

I'll vote! I'm interested in a custom Pi Gateway, especially when the gateway can be flashed with an SPI or i2c-firmware, so you don't loose the standard UART-port for console on the Raspberry Pi.