Ok, so now I have the motor driver working, it is time to install it into the Bigtrak. The first job was to remove the circuit board, key pad and disconnect the wiring. With that done, I connected the motor driver to the Bigtrak's motors, 4.5v power supply and Arduino Uno.

The next job was to connect the Arduino to a separate 9v power supply, then screw the boards in place. Luckily, there are a few screw holes no longer used by the original board.

Once everything was in place I installed a variation of the blink sketch to test for functionality (code included at the bottom of this entry).

To see the Bigtrak in action check out these YouTube videos:

All comments, suggestions and feedback are welcomed.

Test Code

void loop() {
digitalWrite(11, HIGH); // Back
digitalWrite(5, HIGH); // Back
delay(1000); //
digitalWrite(11, LOW); //
digitalWrite(5, LOW); //
delay(1000); // wait for a second

digitalWrite(10, HIGH); // forward
digitalWrite(6, HIGH); // forward
delay(1000); //
digitalWrite(10, LOW); //
digitalWrite(6, LOW); //
delay(1000); // wait for a second

digitalWrite(6, HIGH); // turn left
digitalWrite(11, HIGH); // turn left
delay(1000); //
digitalWrite(6, LOW); //
digitalWrite(11, LOW); //
delay(1000); // wait for a second

digitalWrite(5, HIGH); // turn right
digitalWrite(10, HIGH); // turn right
delay(1000); //
digitalWrite(5, LOW); //
digitalWrite(10, LOW); //
delay(1000); // wait for a second
}

In order to experiment with artificial intelligence, I need a platform to play with, therefore, I have hacked a Bigtrak. This entry is a description of my journey so far.

The Bigtrak is a children's toy which can be programmed, via a keypad, to drive around and shoot things with its 'photon laser'. Inside, there is a main circuit board, 3xD cell compartment (4.5v), LED (Photon Laser), speaker and twin gear box (motors circa 3v, no-load = 150mA, loaded = 500mA ) (image right).

The Plan

Remove circuit board and keypad then replace with Arduino Uno and motor controller.
Test its roaming ability with basic program.
Install sensors. Options including, but not limited to: ultra sonic, light, reflective surface, impact, tilt and sound.
Install actuators. Options include, but are not limited to: stepper motor (360 degree rotation of ultra sonic sensor) and LED.
Design program to allow the Bigtrak to behave in response to environmental stimulus.

Achievements So Far

After working with the Nanode RFX for some time, I decided that the Arduino Uno would be more appropriate for this project. Therefore, after purchasing the Uno, I looked for an appropriate motor controller. I needed something that could handle a peak of 500mA and found, curtsy of the Raspberry PI forum, the "Dual H Bridge DC Stepper Motor Drive Controller Board Module Arduino L298N #236" (long name but should be searchable). After around 20 minutes I had a working circuit (see video).