Primarily made to work with Keyestudio 4WD BT Robot Car V2.0 Kit for Arduino, but should work with any robot with wheels or caterpillars tracks based on Arduino.
ARDUINO CODES:
https://github.com/shikhli/Arduino-Bluetooth-car-remote
There 2 codes for different motor drivers:
1) For Motor Shield V2 motor driver
2) For L298N motor driver
For more info read github project's README file.
WIRING DIAGRAM FOR CONNECTING MOTORS TO "Motor Shield V2.0":
M1 <---> B
M2 <---> B1
M3 <---> A1
M4 <---> A
APP FEATURES:
* Both Classic (HC-05, HC-06) and Low Energy Bluetooth - BLE (HM-10 etc.) modules are supported.
* Analogue Slider control method for more precision.
* "Car" & "Tank" type control modes.
* Automatically displays MAC address of Bluetooth on LED display (last 4 symbols) /only if BLE/
* You can modify Arduino code and let to display any text. There is built-in English alphabet, digits and some symbols (?,.-) inside the code.
SOURCE CODE of this app
https://github.com/shikhli/Universal-Bluetooth-Controller---Android-App-for-Arduino