Nuts & Volts - January 2005

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

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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

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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.