The Crazyradio is a 2.4 GHz radio USB dongle. Currently it's only used to communicate with the Crazyflie Nano Quadcopter but it can be adopted to work with a number of applications that are based on the low-cost 2.4 GHz chips from 
1.USB - Connect to computer
2.Programming/PPM interface - Used for programming and interfacing with a RC remote
3.Antenna connector - Connector for antenna
4.Red LED - Toggles when data is now able to be sent to the quadcopter
5.Green LED - Toggles when data is successfully send to the quadcopter
- Based on the nRF24LU1+ 2.4 GHz SoC from Nordic Semiconductor
- USB bootloader enables firmware upgrades via USB
- Can be used as stand-alone module with RC controller via expansion header. Supports 12V PPM input and power supply. Note: There's still no firmware to support this *feature but it's under development
- Comes with GPLv3 firmware developed fully by Bitcraze from datasheet and a build environment that allows you to develop your own firmware
- Programmable via SPI using expansion header
On Windows 7 the installation of the Crazyradio dongle will fail by default and then you will have to install the driver manually. This page documents the procedure to install the Crazyradio driver on Windows 7. The procedure is very similar on Windows 8. Windows XP allows to chose the driver path at the dongle first insertion
1.When connected, the Crazyradio dongle fails to be installed automatically by Windows
2.When that happen, open the device manager, find the uninstal USB device and right click on it to update the driver
3.In the window popping-up chose “Browse my computer for driver software” and then point out the decompressed driver folder you 
4.Click next, accept installation without verification, and the driver is installed!
All these behaviours can be compile time configured. In the future they might as well be able configurable during runtime using the Crazyflie client.
Radio communication lost If the Crazyflie hasn't received any commander package within 0.5s it will try to level itself. The client sends out 100 control packets per second so 50
consecutive packages must have been lost
If the Crazyflie hasn't received any commander package within 2s it will turn off the all motors.
If the Crazyflie hasn't received any commander package within 5min it will automatically shut down.