READER-TO-READER TECHFORUM
>>> QUESTIONS
Milwaukee Screwdriver
Battery Chargers
I am a soon to be retired
industrial electrician. At work, we use
many cordless screwdrivers, mostly
Milwaukee and Dewalt. I have several
no longer functional 48-59-0180
chargers. It looks like a relatively
simple circuit. I haven't indentified an
in-line chip. Can anyone help with
schematics and components?
Replacement 48-59-180s are no
longer available. Replacement 48-59-
300s are available, but at half the cost
of an entire screwdriver kit.
#9101 Marv Steinhagen
Davenport, IA
Automatic Door Locks
I have a 1984 Cadillac that the
automatic door locks do not work.
The doors lock from a 12 volt
positive pulse from the gear selector
switch as it crosses the reverse
position. This also sends a signal to the
back-up lights which work fine.
Does anyone have a circuit to
lock and unlock the doors?
#9102 Frederick Rembetski
via email
78 September 2010
Electric Fence Monitoring
I currently operate a small 10 acre
hobby goat farm, protected by a
commercial 16 KV, high impedance,
pulsed charge, electric fence spanning
across rolling hills which are "not
visible" from the house. Some of our
goats are natural born escape artists —
as determined to get out as coyotes
and wildcat predators are to get in. I
need a "smart circuit" that can detect
whether: (1) animal fence contact was
just a "one time" brief encounter
(resulting in a successful rebuff); ( 2)
there are multiple successive contacts
within a set time period (as would be
the case of a determined assailant);
( 3) there is a persistent reduced fence
charge (from an entangled animal); or
( 4) there is a total fence failure (due to
a break in or total grounding of
the system). Most importantly, the
circuit must be able to identify which
specific fence segment/zone the
problem is located at for fast response.
In the past, predators have patrolled
just outside the fence eventually
digging underneath it or jumping over
it without contacting it, so some form
of zone based non-contact perimeter
sensing (possibly using air to wire
capacitive couplings) would allow for
early warning of a potential problem.
#9103 Sebastian Sullivan
Makanda, IL
Auto Audio Adjust
Every time I slow down to an
intersection, I turn my stereo down
slighty. I need a device to work
with the brakes and final output;
something with a delay and that
slowly fades back up.
#9104 Steve McKennon
via email
HD Reception on FM Tuners
Is there an HD adapter that can
be added to an existing FM stereo
tuner, similar to the circuits we
added years ago to receive stereo on
a monaural tuner?
#9105
John R. Seeley
Palm Bay, FL
Power Supply for Optional DC
or AC Input
How can I design a simple circuit
that allows me to have the option of
supplying 120 VAC or 15 VDC?
Currently, I have two fixtures: one uses
a LPS24+15V/1.7A 25W input and
the other an external 15V supply.
All questions AND answers are submitted
by Nuts & Volts readers and are intended
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problems. Questions are subject to
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by the publisher. Answers are submitted
Other than that, the fixtures are the
same. I would like to have the option
to plug in AC or to plug in a 15 VDC
supply.
#9106
Chuck Moskowitz
Ann Arbor, MI
Keystone Jack Wiring
I need data/instructions on how to
wire a keystone jack per specs 368A/B.
#9107 Harry Campbell
Wind Gap, PA
Voltage Dropping
I have two circuits in the same
enclosure: one works on 12 VDC and
the other on 9 VDC. I have a 12 VDC
transformer for the one. I need a
9 VDC for the other. I tried with
resistors to lower the voltage to 9 VDC
with no success.
#9108
Pete Theodoulou
Durham, NC
[#4103 - April 2010]
Cat RFID
We have four indoor/outdoor cats.
My plan is to have each of them
implanted with an RFID chip and to
have a sensor over the cat door which
will read them. The door is already
wired to indicate "a cat has gone in" or
"a cat has gone out." Now I want to
know which cat, and also possibly
have the cat door remain locked until
a known cat approaches.
I purchased an RFID reader
module from Parallax and although this
worked okay with the tags supplied,
there was no response from the RFID
chip borrowed from our friendly vet.
Does anybody have a suggestion
>>> ANSWERS
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WHATSOEVER are made by the publisher.
The implementation of any answer printed
in this column may require varying degrees
of technical experience and should only be
attempted by qualified individuals.
Always use common sense and good
judgment!
