Shop Buddy by Kevin Spitzer

Shop Buddy was built over 10 Saturdays by Junior Highschool
students as an extra curricular project.  Shop Buddy is made
almost entirely from scavenged materials.  The frame is a 55
gal. drum cart, the gear motors on the wheels are from junk
vending machines, the controller is a TRS-80  Color computer
from a thrift store.  Shop Buddy has basic bump switches and
dual photo cells for light tracking and measuring.  We have
also mounted a photo cell on a stepper motor to scan light
levels.  A sound chip from a toy allows us to select different
animal sounds at different occasions.  In the works is IR
whisker collision avoidance if we can boost the range to more
than a few inches.  An ultrasonic unit scrapped from a polaroid
camera was attempted but the computer runs basic and I don't
think the kids are up to the task of hand assembling 6809 code.  

The TRS-80 Color computer contoller is a really great unit for
the money (69 cents). It runs a Motorola 6809 processor at 1 mhz
with 16 or 32 k ram.  That doesn't sound like much but it also
has built in extended Basic, keyboard, TV output, cassete tape
interface, 4 channel 6 bit ADC,6 bit DAC, an extra rom socket,
and a card edge connector which is a fully decoded parrallel bus.
I have built simple I/O boards with one chip and power darlingtons
to drive just about anything.  The kids bolt on all kinds of
electrical devices and experiment with control and feedback by
writing simple basic programs.  I have several of these computers
and boards set up so we can develop and test things before trying
them on Shop Buddy.  The kids have a blast gutting components out
of old machines, then bolting things together in a new way and
watching it drive around the parking lot doing what it does on its


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