Crazyflie Android Client
This app lets you control a Crazyflie 2.0 or 2.1 from an Android device via Bluetooth Low Energy (BLE).
Note: The app does not support the Crazyflie 2.1 Brushless.
You can also connect using the Crazyradio USB dongle via USB OTG, depending on your device.
Available on Google Play:
https://play.google.com/store/apps/details?id=se.bitcraze.crazyfliecontrol2