ANKR
ANKR makes a neat little device
you can clip on your keychain and make your keys beep
from your phone. You can also make your phone ring by pressing
a button on the keychain device.
Bluetooth Low Energy (BLE) Hacking
Download the APK for the ANKR app, unpack it with apktool, and
grep the smali disassembly for 'java/util/UUID'.
com/bleon/ankrmanager/Bluetooth/NordicBasedDevice/NordicBeaconDevice.smali
contains the following handy Bluetooth service and characteristic UUIDs:
- 0000180f-0000-1000-8000-00805f9b34fb - BLE Battery Standard
- 00002a19-0000-1000-8000-00805f9b34fb - Battery Characteristic
- 08441600-D1B5-94B4-1ACD-0BB3E2ADB6EE - ANKR Custom Service
- 08441601-D1B5-94B4-1ACD-0BB3E2ADB6EE - Firmware Version Characteristic
- 08441602-D1B5-94B4-1ACD-0BB3E2ADB6EE - Bootloader Characteristic
- 08441603-D1B5-94B4-1ACD-0BB3E2ADB6EE - Buzzer Characteristic
- 08441604-D1B5-94B4-1ACD-0BB3E2ADB6EE - Unknown Characteristic
- 08441605-D1B5-94B4-1ACD-0BB3E2ADB6EE - Button Characteristic
Funny enough, if we write a nonzero byte between 0 and 10(0xA) to the buzzer
characteristic, the device emits that number of beeps. From this, it's trivial
to develop an app or nRF52 based device that scans for the ANKR Custom Service
and causes them all to beep.