[Cialug] OT: continuity test

[Dave Weis]

That wouldn't be too bad, a small box with two 1/4" stereo jacks. Put 
the negative side of the battery on the shield and the positive on the 
tip and ring. Put an LED from tip to shield and ring to shield on the 
other jack. You'll need a resistor of some unknown resistance between 
the battery and the LED's though, 330 ohm sounds familiar for some reason.

dave



David Champion wrote:
> For you electronics gurus out there...
> 
> For our SCCA autocross timers, we have a set of cables that go from the 
> timer head unit, to a photo sensor head out on the course (similar to a 
> garage door safety sensor, bounces a light off a reflector). The cables 
> have 3 conductors, we're using a fairly light gauge stranded wire, 
> probably about like what's in ethernet cable. The connectors are 1/4" 
> stereo headphone jack style (3 connectors). The cables may be up to 
> about 250 feet in length.
> 
> Occasionally someone will get off course and run over one of the cables 
> with their car, and they get some rough treatment at times, may get 
> kinked, and get dragged around parking lots. I'd like to have some kind 
> of way to do a quick cable test on them during setup to help shorten the 
> troubleshooting time, so we'd know whether or not it's a cable issue, or 
> another issue with the photo sensor.
> 
> Anyone have an idea of a simple device we could build to test the 
> cables, or would we be better off using a multi-meter, or another 
> pre-existing device?
> 
> -dc
> 
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-- 
Dave Weis
515-224-9229
djweis at internetsolver.com
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