Hacking the Fluksometer - It's a mote!

Cheers everybody.
This goes to let everybody know, that some 5 fearless knights from southwest germany set out to repurpose the fluksometer.

We need to measure humidity and temperature at several places within our lab facilites, which have in between them lots of solid steel-inforced concrete and big distances. Wireless might be there, wired networking is there for sure. We're on a very tight financial plan, so we figured, we want to invest a maximum of 100 EUR per point of measurement. Plus, we need to have a system up that will work its magic without us running around and taking care. Once it's there, we need to use it, not care for it every half year and change batteries, or do the collecting-run (read-out USB-Data-loggers). Chris, one of my colleagues suggested having a look into the workings of the flukso. And, because it's such a well engineered idea, we figured, there is not much to do to make the fluksometer into a pretty much universal mote.

Our ideas revolve around:
- use the SHT 7x series of sensors: at about 30 EUR you get both values, temp. and rH, and it's pre-calibrated. Digital read-out. The best bang for the buck, really. http://www.sensirion.com/

- re-program the sensor board atmega to read the SHT

- re-work the openWRT datapusher on the Wireless board

- sever-side: no final decision yet.

We contacted Bart already on his ideas re: the fluksometer v2. Lots of good ideas in there, to get a hint look at github.

From our point of view:

Let's use a fat Atmega like the ATxmega128A1 on the sensor board. More RAM, more interrupt capable pins.
http://atmel.com:80/dyn/resources/prod_documents/doc4064.pdf
price: Atmega 168 @ mouser.com: ~3 EUR
Atmega 128 or 1280: ~15 EUR
Atxmega 128A1-au: ~8 EUR

Let's have a standardized, pluggable i/o-header, so everybody can either plug in a small screw-terminal input-board or another self-designed sensor-board.

And let's have i/o on these, the lot.

Let's move the r/c signal processing on the plug-in-terminal board, so everything is free to be tinkered with.

Let there be +Vcc on th header, directly from the power rail. So tinkerers can up/downconvert to supply their sensors, without compromising the internal power rails of the router board.

Finally, let there be optional power over Ethernet!

Anyhow, let's have this forum thread to have a quick survey of what you guys out there think about the plan. What are your must-haves for a mote?

All the best

Thomas