The Radio Minion is a small, low cost dev board with a wireless radio, ready for the Arduino environment with no need for your own Arduino board (Arduino is built-in).

This little guy comes fully equipped with:

ATmega32u4 Atmel Chip- The same one the Leonardo uses (that's the new one!) This allows us to have built in USB support. With that you can make minion appear to your computer as a keyboard, mouse or a joystick.
Micro USB Port- for programming ease.
6 Analog Lines, and 14 Digital +3 extra lines that can be used as digital lines
3.3V Power Regulator- You can power the minion from either your USB port or any voltage supply up to 16v. It is also made for lower power applications. The power regulator takes 2 microAmps when active.
USB Powered or External- In order to allow the Minion to operate from either the USB or external power we added a power switching system. When you plug it into the computer minion will automatically switch its power to the USB's power supply. This helps prevent voltage problems between power sources. When there is no USB power it will pull from the external power.
433 MHz Radio from HopeRF- The RFM12B. There is an extensive library for Arduino for this radio that makes getting up and going a snap. (Also available in different frequencies 915MHz and 433MHz). Ideal range for the RFM12B is upto 100m!!
Compact: small, we mean really small, like 1.125" X 1.5625" small! For comparison the Arduino Leonardo's dimensions are 2.95" x 2.08". That's more than 3 times larger than the minion.