PICMAN 2000 is driven by a
single PIC16F84 microcontroller and will perform up to fifty
combinations of manoeuvres involving left and right, forward and back movements
and a pause.
Like all good robots, he lets you know when he’s turning and
stopping with his built-in turn indicators and brake light.
It’s a simple project which we believe will be very popular
with schools as they move into this new phase of the information technology age.
PICMAN 2000 will not only give hours of entertainment, it will teach a lot about
how basic microcontroller programs work. Build PICMAN 2000 now and you could
become the twenty-first century’s Bill Gates!
Above photo shows PICMAN 2000 going away from you, while the shot on the facing page is comin' right at ya! The front wheel doesn't steer: all direction control is performed by the instructions you give to the PIC which in turn drives the stepper motors.
Apart from the PIC microcontroller, there are not very many
other components – just a few to supply appropriate power to the robot’s drive
motors. There are also a few switches which not only control various functions
(such as power on/off, speed, etc) but also allow you to program the PIC (and
therefore the robot). Finally, there are the previously-mentioned blinkers and
stop light which are LEDs driven directly from the PIC chip.
Unlike some previous robots, PICMAN 2000 has a single 6V supply
derived from 4 x AA cells. This provides power for both the logic circuitry and
the motors.
And also unlike some previous robots, the motors power the back
wheels with a free-turning front wheel (castor).
With the exception of the battery pack, three switches and the
rear (brake) LED, all of the electronics is assembled on a single PC board.
Mechanically, everything is mounted onto two small pieces of clear acrylic sheet
(although other materials could be substituted) which are themselves glued to
two back-to-back stepper motors.
The drive shafts from the stepper motors are fitted with cogs
which friction-drive the large rubber-tyred wheels. Turning is achieved by
driving one wheel faster than its mate or even one wheel in a reverse direction
to its mate.