The Colorado Micro Devices RadioBlock is an IEEE 802.15.4 FCC and CE certified wireless modem. It has a simple UART interface to make it easy to drop into your end product or to experiment with. A standard 100 mil pin spaced header means you can plug it right into many common boards: Arduino, Raspberry Pi, BeagleBone, it’s easy – No special pin configuration or adapter board needed!
It happens to slide perfectly onto the Raspberry Pi's UART pins:
Here's the close up of the front and back, it has an Atmel 802.15.4 radio chip and a NXP Cortex M0 microcontroller and is powered by coincell:
The "remote" RadioBlock in this setup is embedded inside a door lock to allow one to lock or unlock via an interface on the Raspberry Pi:
Colorado Microdevices is competing in the IPSO Alliance Internet of Things challenge
It also fit on the Arduino nicely too:
Finally, here's my complete photo gallery of the Sensor Expo: