Who have every played with his toy RC car?
Today you can turn your old RC car into an advanced Android RC car using Arduino and Bluetooth shield in simple straight forward steps.
First you need to get the card that fits all of those simple components required for the new control circuit.
What you’ll need:
Arduino UNO
HC-06 Bluetooth shield
L293D IC
12v Lipo battery pack
Some resistors
Android program
https://play.google.com/store/apps/details?id=braulio.calle.bluetoothRCcontroller
Source
https://www.instructables.com/id/Arduino-Bluetooth-RC-Car-Android-Controlled/