■ FIGURES 2A, 2B, and 2C. The LEGO Spybotics remote control module sports a nice AAA battery box, IR transmitter,
pushbuttons, and an LED.
HARD DRIVE HARVEST
One item that is almost always
able to yield some useful parts after
being opened up is the venerable
computer hard drive. Some older
drives (especially older 5-1/4"
MFM/ST-506 type drives, and some
5-1/4" floppy drives) contain very
nice stepper motors (Figure 3), gear
trains (Figure 4), sensors (Figure 5),
and other useful bits for the hobbyist.
If you can't find this vintage of hard
drive, don't despair! Similar parts
can be found in most CD/DVD
Most all modern 3. 5" hard drives
(Figure 6) contain recyclable and
useful parts including very powerful
neodymium magnets, .100" jumpers,
precision screws, bearings, and other
hardware (Figure 7), as well as the
shiny data platters. Disassembly is
simple, quick, and fun and the parts
yielded are usually useful and worth
your time to harvest.
Another item I hunt for at thrift
stores is the oft-maligned wall wart
(given its name due to its appearance
as an unsightly growth on the wall).
It always seems I need a specific
voltage, amperage, plug type/size, or
gender that I don't have on hand. I've
been known to walk out of a thrift
store with 10 or more of these babies
(Figure 8). This way, I can always dig
out an acceptable, portable power
supply for a small experiment.
In the Austin, TX area, wall warts
at thrift stores typically go for
between $0.50 and $2.00. You can
also often discover orphaned "brick
style" power supplies commonly used
to power laptop computers. These
tend to be higher voltage/amperage
and can sometimes produce multiple
supply voltages so they have the
potential of replacing a couple of
wall warts. Keep your eyes peeled
(and possibly take a magnifying glass
with you) as the writing on these can
be very small.
KEEP IT ON THE
In most cases, my idea of "low
cost" is below $100. I know this will
probably be different for each
person, but I stay with this number
for two reasons. One: sub $100
purchases are less likely to be picked
up on the radar by a "significant
other." Two: if you are discovered, it’s
easier to recover from because it’s
about the same cost as a nice dinner
out for two.
So, with $100 as the benchmark,
can we really buy much in the way
of "new" robotics parts or projects?
The answer is a resounding YES!
Compared to a couple decades
ago when a useful robotic training
system cost thousands of dollars
(think HERO-1), today's robotics
offerings are immensely powerful
with exceptional price/value ratios.
For example, Parallax offers a
complete two-wheel robot kit with
their ever-popular BASIC Stamp II
at its heart that retails for $99.99
(careful online shopping can nab
one for $75 or less!).
The "Scribbler" (Figure 9) is a real
programmable robot with the ability
to move, use sensors, evaluate inputs,
make sounds, and even draw pictures
(hence the name). It also includes a
■ FIGURE 3. This is what’s left after
removing the platters, platter drive
motor and circuit board from a dead
ST-506 hard drive.
■ FIGURE 4. The stepper motor drives
this nice metal platform that used to
position the hard drive's magnetic
■ FIGURE 5. On the other side of the
platform, an optical sensor with an
adjustable interrupter is affixed to
the stepper motor’s shaft.