http://www.techdesign.be/projects/025/025.htm
* Low power operation (8-10 mA @9V) with PIC 18F452 (TX) and 18F2550 (RX) microcontrollers running at 4 MhZ.
* Sampling rate: around 3 samples/sec.
* Max. distance between the RX and TX circuits: 30m indoors and 100m outdoors.
* Software is 100% upgradable with a simple bootloader.
* Low power LED blinks when sending / receiving data.
* TX circuit: PCB Dimensions: 30 x 31 mm or 1"18 x 1"22, weight: 8 grams.
* RX circuit: LCD contrast adjustable by user.
* RX circuit: PCB Dimensions: 40 x 41 mm or 1"57 x 1"61, weight: 10 grams.