As discussed in another
thread, it needs only a plain vanilla IrDA interface to communicate with a Gossen Metrawatt MetraHit meter from the Starline series. In my case the Metrahit X-Tra, but it should be the same for the Extra, Energy and so on.
While I have a working breadboard approach based on an "IrDA2 click" and a Chinese FTDI adapter, I wanted to create something more convenient.
I tried my best to allow a correct USB suspend mode by using the #PWREN/#SLEEP outputs as enable/disable lines for the IrDA part.
My idea is to fit the PCB into the a laser cut acrylic case so it can be mounted to the meter just like the real thing.
Anyway, before I order at Elecrow or so, I'd be nice if someone could have a look and tell me if I overlooked any blatant mistakes.