Another possible approach to defining data exchange language-independently is Google’s scheme of protocol buffers.
It’s funny how even early experiences change the way you think about a design. Two minor changes to SleepySketch have been suggested by early testing.
Keeping the microcontroller asleep as much as possible is a key goal for a sensor system, so it makes sense to organise the entire software process around that.
Any sensor network has to represent sampled data somehow. What would be the most friendly format for so doing?