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  


E-Mail: Stiglie@aol.com

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