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98 March 2007
I have a symphonic SL 2940 VCR
that I would like to use as a security
component with camera and motion
sensor to record for five to 10 minutes
as motion is sensed and repeat, if
necessary. Audio is not required. Hope
somebody has designed a simple
circuit for this purpose.
#3071 Paul Kozlowski
I built an ATMEL-based stepper
controller that sent the step commands
through four power MOSFETs that
connected directly to the coils of a
"four volt, 1.2 amp/phase" unipolar
stepper. It was an inexpensive motor
but it worked great — good torque and
speed and started right back if stalled. I
bought more of the "same" motor — it
had a different label and didn't work at
all — stalled, shook, and no torque. I got
several different motors from different
companies, all with a rating of 4-5 volts
at 1-1.2 amps (I'm using a switching
supply rated five volts, 3. 5 amps) and
they all respond differently. None work
as well as the first (and cheapest)
motor. The MOSFETs have protection
diodes and I tried adding diodes to the
power lines — no change. I bought a
commercial controller with a motor
rated 12 volts, . 4 amps, which turned
out to be a 12-volt version of my
original motor, and it worked very well.
The other motors run better with that
controller, which has variable current,
but still vary in performance. I can't (nor
can the motor company) figure out
why there is so much variation in
output with motors with the same
ratings. Is there some way I can get
the rated power out of these motors
without spending a fortune? Is there
another motor rating or spec that I can
use to judge these motors?
#3072 Dan Schwartz
I am working with the old, very old,
MS-Basic Interpreter. It is limited to 16
digits in double-precision mode. If I try
to multiply two 15-digit numbers, it
slips into "Exponential Notation" mode:
Thus, a 15-digit number TIMES
another 15-digit number would have a
Is there a way to convert — in
MS-Basic — this "Exponential Notation"
into all 30 digits? Also, can the reverse
be done in MS-Basic? I would like to
work with 100 digit (or more) numbers.
Is there a book that can help me
with this problem?
#3073 Stuart B. Wahlberg
PO Box 1233
Blythe, CA 92225
I have been told by someone
whose judgement and knowledge I normally trust that malware exists that will