Got my 2nd raspberry pi today. Coinciding with the discovery that pin 10 on the arduino board I was going to use to submit data from the currentcost cc128 meter to mqtt seems to have a duff pin 10 (which makes it rather hard to use the ethernet shield), I decided to see if I could instead have the 3.3v RS232 from the cc128 drive the 3.3v RS232 on the raspberry pi (through 2 gates of a CD4049 running from the rPi 3.3V rail to protect the rPi if something went wrong). After finding an old floppy cable to rip apart and bodging together a LEGO case (based on the design by Biz but hacked because of the over-sized connector I’ve used for the i/o port), it was a matter of “apt-get install mosquitto-clients python-serial”, copy the script over from the server currently doing the job (which has a long unreliable USB cable to the cc128), hack it to send the data to the server rather than localhost, and voila! works first time.
Disturbingly this actually costs less than an arduino + ethernet shield. The form factor is a little more awkward though (ports at both ends of the board, no screw holes), so getting it into a case along with other bits and pieces will be somewhat more awkward; ideally it would be good to have a tall case with enough room in the upper part to hold a pcb for additional components.
