Arduino – Line following robot – part 4 (Motor driver)

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Part 3: Motor driver board

We used 2 gear motors with rubber wheels. 14 cm Zip/cable ties were used (2 per each motor) to fix the motors to the base plate.

It has the following features:

VoltageDC 6v
Current (no load)120 mA
Reduction rate48:1
RPM (With tire)240
Tire Diameter66 mm
Car Speed (no load)48 m/min
Motor Weight50 g

The motor driver chip L293D (D=dual direction) was a very easy chip to implement. The enable pin is used as PWM to control the speed of DC motors. We thought of 2 speed levels controlled through a jumper. Perhaps one for slow testing mode, the other for game mode!

VDD is for 6V dedicated motor power supply.

Here’s the test code. Short the pin 13 to positive supply and then to negative supply and watch the motors turn either way.