Hack your RC toys for controlling motors from smart phone or just drive two motors over Bluetooth. This device provides Bluetooth service for individually controlling two motors with PWM signals.

The main features are:

• Control dual h-bridge from Android phone or iPhone over Bluetooth Low Energy.
• Drive two brushed motors with PWM.
• Control up to 4 lights.
• Input voltage 4-9V.
• Uses LB1836 h-bridge.
• Provides Bluetooth Low Energy service for your own applications.

Using Bluetooth API

The control board main part is a cc2541 module by Texas Instruments. This module provides 8051 CPU and Bluetooth radio in one package. The main part of firmware is its Bluetooth Smart GATT table that defines device services and characteristics. So this firmware has one service for controlling a car and this service has several characteristics/attributes:

• 0xacc2 – First motor control – the value from 0 to 700, there 350 value keeps motor off, 0 lets it run backward at full speed and 700 lets it run forward at its full speed (the intermediate values could be used for controlling motor speed, make it run a little bit slower or faster, lower and higher values could be used).
• 0xacc1 – Second motor control – the value from 0 to 700, there 350 value keeps motor off, 0 lets it run backward at full speed and 700 lets it run forward at its full speed (the intermediate values could be used for controlling motor speed, make it run a little bit slower or faster, lower and higher values could be used).
• 0xa101 - Lights attribute – depending on written values, the Bluetooth module turns on/off the specified lights. (16-bit number for controlling each individual light. 0x0001 – first light on, 0x0002 - second light on, 0x0004 third light on, 0x0008 – fourth light on, 0x0010 – fifth light on.)

Connecting:

• Connect 4-9V battery to the power in pins.,
• Connect two motors to motors pins.
• Plug leds to the leds connector (leds GND goes to pins, and directly provide power to the through resistor from battery)

Demo applications:

• Download the Android app from Google Play
• or Download iPhone app from App store
• Use connect button to connect to your RC car (the name initially would be some random number, that could be changed in settings)
• User arrows or accelerometer to control steering and throttle.

Source code and schematics:

• all code is available at the GitHub
• Demo project is available on GitHub as well.