PHOTO 3. This is that auxiliary application I was talking
about. However, it is running on the PIC16F690.
The PIC16F88 is assisting by doing the math that
you see in the display.
Wire in one of the PICDEM lab development board’s
N-channel MOSFETs between the motor and ground, and
drive the MOSFET gate from GP2. Changing the TMR0
value changes the period of the square wave that is being
produced at pin GP2 which, in turn, changes the speed
of the motor. We’ve just proven that you don’t have to
resort to 80-pin PIC devices to drive large LCDs, send
messages, process analog data, or spin motors. SV
5 reflectance sensors on underside
The Pololu 3pi robot is a high-performance, compact
mobile platform featuring:
Two metal gearmotors
Five reflectance sensors
8×2 character LCD
Three user pushbuttons
Buzzer and LEDs
All peripherals are connected to an ATmega328P
microcontroller running at 20 MHz, with free C-programming
tools, libraries, and support for the Arduino environment.
High-traction silicone tires
Speeds exceeding 3 ft/sec
using innovative constant-voltage motor supply
robot diameter is 3π cm (~ 3. 7 inches)
Find out more at
www.pololu.com/3pi or by calling 1-877-7-POLOLU.
SERVO 08.2009 47