Robert Ross

Engineering Projects - Bi-Directional Motor Driver

"Plug your motor in and drive via serial command"

The Bi-Directional motor driver project came about as a matter of necessity for other projects - namely the ROV and my PhD robotics research. The aim was to create something to drive motors up to 5A at 12V in both directions. Incorparated into the design is the option to either drive the motor under serial control (allowing the designer to hang several motors off a common serial bus) or directly supply a direction and PWM signal to drive the motors. For safety a hardware enable bit is provided along with DIP switches to allow upto 4 different 'motor addresses' to be configured.
The serial messages send a generic message similar to the AT strings produced by a GPS receiver. The message specifies the motor address (0-3), the motor direction (forward/backward) and the speed (0-255). An Atmel AT-Tiny13 microcontroller is used as the brains behind the motor controller and features a custom software driven recieve UART. The circuitry driving the motors is classic H-Bridge with pairs of N-Channel and P-Channel FETs interfaced to some AND gates from the 74HC08 package to prevent shoot through on the H-Bridge.


Motor Driver Photos:

Etched and drilled PCB for the motor driver	Close up of the FET H-Bridge section	Birds Eye-View of the completed circuit