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. In a hover test we got it to fly almost 8min but during active flying it flies for about 5-6min.

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 about 20min to charge and the green LED 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 but you will have to come up with a different fastening then the double sided tape we use. Also you will have to charge them with a stand-alone single cell capable LiPo charger for it to be any idea.

The Crazyflie is controlled with the Crazyradio. It uses the nRF24L01+ 2.4 GHz chip from Nordic Semiconductors which is commonly used in commercial HID devices. We chose this chip because it is low power, low latency, decent range, easy to work with and relatively cheap.

As with all radio communication it depends. It depends on the environment, radio interference, chip production variations, etc. In a couple of line-of-sight tests outdoor we have gotten from 50 to 80 meters range in the 250 Kbit mode, higher data rate decreases the range.

The Crazyradio has been designed to work as a radio dongle connected to a USB port but has other capabilities.

• We gave it an expansion header and it can work solely from this header, see schematics. The header accepts power up to 16V and could read a PPM signal so it is possible to make it work as a R/C transmitter module, but we have no code for it now and it would be a bit hackish.
• It can be used in “headless mode” on a Raspberry Pi
• It can be connected to an Android device with USB host functionality.
  • We are currently working on an Android client which is in beta stage. Github Repository.
  • Android client user guide

The e-sky R/C transmitters use the nRF24L01 chip, compatible with ours, so it is possible to control the Crazyflie using the e-sky transmitters. Firmware support is in beta stage. Also see “Is a PC required for the Crazyradio?”.

The Crazyflie is using the PCB itself as the frame. The PCB is made of FR4 which is a strong and lightweight material. We have tried to find a good thickness for the arms so that it is strong but also flexible. We want it to be flexible so that it bounces during a crash which will reduce the g-force chock imposed on the electronics. It has no problem handling low speed crashes but if you push it too it's limits and you fly 30 km/h into something hard you probably will damage it. Most of the parts can be replaced but if you are very unlucky you break one of the arms. We are working on 3D printed part that can be used to repair the arm in case of an accident such as this.

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…

First steps towards a bigger Crazyflie:

• Brushless driver for the Crazyflie - Blog article
• Forum post with additional pictures

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