Tech Forum
Tech Forum
QUESTIONS
I recently acquired about 20 four-channel 29 MHz radio-controlled cars
and when used as-is, they range as far
as 30ft indoors. After slight mods, still
good range, but once I install it in my
car, the range becomes inches. Why
is this? Does the car just block/
absorb that much of the signal?
#07051 Kevin Harris
St. Louis, MO
projects, without the need to
construct the remote control itself. I'd
think other experimenters could
utilize such a receiver to add remote
control capability to their robotic and
other electronics projects. I suppose I
could try to salvage this circuit from
an old TV or VCR, but since I'm not
interested in having a tuner for TV
signals, I was hoping for a simpler
circuit. I'm also looking for a good
book on how to troubleshoot these
circuits in various TV and VCR
applications.
#07052
came with Mac software to download
the pictures. I have been puzzled that
I can't transfer pictures directly from
the SD card, although I can download
through the camera.
I recently bought a new three
megapixel version for a friend and
haven't been able to download
pictures to my Mac. The CD that
came with it (16-3844) seems to only
have Windows drivers. I tried to use
the driver from my old Flatfoto 1.3,
but it doesn't work. I also tried to
access the SD card and that doesn't
work either.
RadioShack has been no help.
Ideas anyone?
#07053
Dave
Millville, NJ
I want to build a receiver circuit
for a TV remote control. With the
number of cheap "Universal" remote
controls that are available, I'm hoping
to be able to use one of these to
control some of my electronics
Dwight Johnson
Booneville, MS
A couple years ago, I bought a
Flatfoto 1.3 Megapixel camera. It
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I have a number of IF
transformers with no color-coded
leads, and the primary and
secondary have similar DC
resistance. How can you determine
the primary from the secondary,
specifically the plate (collector) from
the grid (base) leads?
#07054 Richard H. Abeles
via Internet
I'm using motor controllers with
LMD18200 amplifiers in a robotics
project, and the amplifiers literally
blow up if the motor power is
reversed! I'd like to find a simple way
to protect from reverse polarity, but
without an inline diode or rectifier
because of the voltage drop
associated with diodes, especially at
higher currents when the motor really
needs all the voltage it can get. I've
been thinking of using a relay
powered by the motor power source
(usually a battery), but since my
motor battery, can be anywhere from
6 to 24 volts there could possibly be
too much or too little voltage to run
the relay coil.
It would be nice to avoid old-fashioned fuses, as well.
#07055
Stew
via Internet
I would like to add FM radio
signals to our prison cable system
JULY 2005
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