TIKE by Lenny Urbano

TIKE is a small 2-wheeled robot utilizing differential
steering for navigation. Using 2 Radio Shack project
box covers, I glued 2 modified futaba S3003 servos for
continuous rotation onto a metal cover and screwed a 5
inch screw through both plates and bolted them off. I
fashioned a circuit board deck by cutting a 5 1/2" by
4 1/2" rectangle of plexiglass and mounting it on the
remaining 5 inch screw clearance. Adding a grid of
velcro strips on the deck to ease the robots construction
aided its modularity. 

TIKE's brain is a Parallax Basic STAMP I with a single
8 I/O pin port. 4 lines are required for driving TIKE's
high power H-bridge motor control circuit(MOSFET). 2 of
the remaining 4 pins are utilized by tactile sensor
switches. This leaves only 2 pins for other sensors/
actuators. I'm working on implementing photo-electric
(cadmium sulfide) sensors and a condensor microphone so
that TIKE will exihibit a roach-like behavior: wandering
around aimlessly until a loud noise scares him into
finding a dark place to hide, and only returns to
wandering after a considerable time of silence. 


TIKE cost me 30$ for both servos, 40$ for the high power
H-bridge, $65 for the BASIC STAMP I and the carrier
board and about 10$ in plastic and plexi-glass plates
and screws and bolts. A total $145. Though I'm sure if
were to manufacture all the circuitry myself and
substitute an MC68HC11A controller the cost would be
around 60$. This is my first wheeled robot, I thought
it turned out great considering I took only 2 nights
to build it.

The only problems I encountered with TIKE were power
management and tire traction. I initially let him roll
on the plastic Futaba servo horns which caused him to
slip severely on my tiled floor. I tried putting a thin
layer of glue around the edge, which worked, until it
started getting worn away and stringy. I got the idea
to glue on a KINEX plastic wheel that has a rubber edge
after seeing my brother play with it. The traction is
excellent. As for power, I wanted to have TIKE employ
a 1.3 amp 4.5 volt cell-phone battery that provided
excellent motor power and a 9v for the stamp. But the
cell-phone battery was awfully heavy and because I
haven't implemented any casters underneath the frame,
he dragged his back-end on the floor.

I now use 2 9 volt batteries: 1 for logic (the STAMP
regulates it down to +5v) and 1 for motor driving. Both
supplies are opto-isolated on the H-bridge circuit.

Several more TIKE's together will serve as AI platforms
to test a theory of mine about artificial learning. I am
16 years old and hope to one day attend the Massachussetts
institute of technology. 

More info about TIKE can be obtained at my web site which
is still under construction at  

HTTP://members.aol.com/Stiglie

E-Mail: Stiglie@aol.com


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