Tech Forum
Tech Forum
QUESTIONS
I have an RV and I installed a
homemade electronic rear-view
mirror. I already had a 5” monitor and
connected it to a $39.00 CMOS black-and-white camera with 0.1 lux light
sensitivity. It works fine, but the image
is opposite from a mirror view when
viewed on the monitor. Isolved the
problem by pointing the camera
vertically into a mirror positioned at
45 degrees to the rear.
There are cameras with mirror
switching capabilities, but I’ve been
unable to locate one with 0.1 lux or
better sensitivity. I would like to know
about modifying an existing unit or if
reversing the function is built into an
LSI chip where I can’t get to it? A
functional diagram or schematic of a
camera would be helpful.
#1051 Anonymous
via Internet
checksum error. When I plot a
drawing, it plots to one side and only
half of the drawing is on the page. HP
does not support this plotter any
more and I am having trouble
acquiring information on how to
troubleshoot. Where should I start?
#1053 Alex Malachowski
via Internet
I am looking for a simple on/off
switch that can be triggered by
electrodes placed on the skin. It
needs to have a sensitivity
adjustment. I would also like to have it
opto-isolated for safety. Any
suggestions or places I can look?
#1052 Chris Tauscher
via Internet
Anyone know of an after-market
lens to convert a common PC board
camera into a microscope with a
magnification between 60 and 150X?
#1054 Joe R.
via Internet
I have acquired an HP 7580b
plotter that is mechanically sound.
When I turn it on, E02 is displayed
after a self-test. The operator manual
says it’s a microprocessor error/ROM
This is a READER-TO-READER Column. All
questions AND answers will be provided by
Nuts & Volts readers and are intended to
promote the exchange of ideas and provide
assistance for solving problems of a technical
nature. All questions submitted are subject to
editing and will be published on a space
available basis if deemed suitable to the
publisher. All answers are submitted by readers
and NO GUARANTEES 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 judgement!
Send all material to Nuts & Volts Magazine,
430 Princeland Court, Corona, CA 92879,
OR fax to (951) 371-3052, OR email to
forum@nutsvolts.com
ANSWER INFO
• Include the question number that appears
directly below the question you are responding
to.
• Payment of $25.00 will be sent if your answer
is printed. Be sure to include your mailing
address if responding by email or we can not
send payment.
• Your name, city, and state, will be printed in
the magazine, unless you notify us otherwise. If
you want your email address printed also,
indicate to that effect.
• Comments regarding answers printed in this
column may be printed in the Reader
Feedback section if space allows.
QUESTION INFO
To be considered
All questions should relate to one or more of
the following:
1) Circuit Design
2) Electronic Theor y
3) Problem Solving
4) Other Similar Topics
Information/Restrictions
• No questions will be accepted that offer
equipment for sale or equipment wanted to
buy.
• Selected questions will be printed one time
on a space available basis.
• Questions may be subject to editing.
Helpful Hints
• Be brief but include all pertinent information.
If no one knows what you’re asking, you won’t
get any response (and we probably won’t print
it either).
• Write legibly (or type). If we can’t read it, we’ll
throw it away.
• Include your Name, Address, Phone Number,
and Email. Only your name, city, and state will
be published with the question, but we may
need to contact you.
I recently purchased a
communications test set for aligning
my ham radio related equipment. The
output generator's frequency is set
using thumbwheel switches. Although
I have had no trouble aligning
receivers with this piece of test
equipment, I got quite a surprise
when I attached three frequency
counters to the output. The readings
go wild, but — when I connect them to
older signal generators — the
responses are as expected. After
hooking the test set to my
oscilloscope, I saw the reason. The
signal generator is synthesized, not a
pure sign wave, and is chock full of
harmonics.
How, if at all, can I filter the
output sufficiently so a frequency
counter can be properly used? A
series of low pass filters lined up to be
switched in and out up to 1 GHz
seems a little far fetched.
#1055 John Ciperano K4EBC
via Internet
F
o
r
E
l
e
c
t
r
o
n
i
c
s
NUTS & VOLTS
E
v
e
r
y
t
h
i
n
g
I’d like to use X10 cameras and
receivers — such as those sold by
www.x10.com — to beef up the
security of my home, inside and out.
The problem is that the units do
not secure their transmissions, which
leaves me vulnerable to outsiders
seeing inside my home, knowing
where things are, and whether or not
someone is at home. I’ve contacted
the resellers and they confirmed they
have no security.
94
JANUARY 2005