This is where we try to collect the most frequently asked questions and answers to them.

It can fly up to 7min and depending on how you fly it, the time will decrease.

It is charged using a standard micro-USB connector commonly used by smartphones. You probably have one of these cables at home. You can charge it from any USB unit that can supply 500mA, most computers and adapters do. It takes up to 40min to charge and the blue LED (M3) will tell you roughly how charged it is by how long it is lit. When it is fully lit it is fully charged.

Yes, you can hot swap batteries.

Yes, as long as it is not to heavy, it is a single cell (3.7V), it fits and that the polarity is correct you can do so. A higher capacity battery will give you longer flight times but will also decrease agility. We recommend batteries with at least 15C continuous discharge rate.

The Crazyflie 2.0 can be controlled with the Crazyradio or Crazyradio PA from a PC or with a mobile device using Bluetooth Low Energy.

Here is a list of requirements for the mobile device

• Bluetooth Low Energy (BLE) or sometimes called Bluetooth Smart support.
• Runs Android 4.4 or newer
• Runs iOS 7.1 or newer

Since Android is available on many different devices, it is not certain it works even though it fulfills the requirements above. We have therefore created a list of devices it has been tested on so please give us feedback if it works or if it doesn't with your device. iOS devices is a bit more consistent and the support should be much more extensive. Windows mobile devices does not have any support yet.

As with all radio communication it depends. It depends on the environment, radio interference, chip production variations, etc. It also depends on if you use the Crazyradio, Crazyradio PA or a mobile device. We have done a couple of line-of-sight tests with little interference outdoor with the different configurations:

• Crazyradio: Up to about 100 meters range in the 250 Kbit mode. (The uplink, Crazyradio, is the limiting the range)
• Crazyradio PA: Up to about 1000 meters range in the 250 Kbit mode. (The downlink, Crazyflie 2.0, is the limiting the range)
• Mobile device: Up to about 20 meters range. (The uplink, mobile device is limiting the range)

Currently you can not but we plan to develop expansion boards with R/C receiver support.

This can be done with the BigQuad expansion deck. It's working, but not yet a turn-key solution.

The Crazyflie 2.0 is using the PCB itself as the frame. The PCB is made of FR4 which is a strong and lightweight material. Attached to that is the motor mount which is a bit flexible. The motor mount is designed in such a way that it will break in case of a violent crash and not the PCB or electronics. The motor mount is very easy to change and cheap. We have not yet been able to break anything except the motor mount or a motor during violent crashes and some have been from 30m height right on to concrete. It is not unbreakable though so handle it with care!

As for the communication protocol, yes it is. So all libraries that have been made in Python, Ruby, C, C++, Java, etc. will be able to control the Crazyflie 2.0 the same way. The firmware is also intended to be backward compatible but we are not there yet and we can't promise anything before we have something working.

Yes, it could. All the key components are there to control a quadcopter of any size. There is yet no firmware support for this though. However, imagine having it dockable into a big frame which could carry it a long way and then just release it so it can enter a small area where the big frame can't get to, Sci-Fi…

Yes, it can. ⇒ BigQuad expansion deck

Not yet, but there is ongoing development in this area:

• using onboard sensors (e.g. the barometer in the 10-DOF version) to achieve a “hover mode”: http://forum.bitcraze.se/viewtopic.php?f=6&t=523
• using extra sensors (e.g. an ultra sonic sensor): http://cfusting.wordpress.com/2013/07/28/quadcopters-and-spatially-centric-data
• using external sensors (Camera, Kinect, etc.)
  • First test with OpenCV
  • Autopilot using Kinect and a PC
• Autopilot discussion on the Bitcraze forum

• Before dealing with an autonomous swarm, maybe deal with one autonomous Crazyflie first. ;)
• Not yet a swarm, but at least two Crazyflies flying next to each other → Crazyflie Swarm Precision Position Control - YouTube video

There is ongoing development in this area:

• First FPV flight
• Working FPV Camera setup with realtime HUD
• Working FPV setup for Crazyflie 2.0