Re: Data Acquisition

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 

 > Hi,
 >
 > Don't forget, a meter can be set next to a clock and they can be watched
 > with a camcorder.  If you already have the stuff, that costs zero.  If you
 > have a video capture card or one of those webcam things (cheap now too),
 > you can find free software out there to grab and store the image say every
 > 15 seconds.  Might not impress NASA, but it sure is cheap, easy, and just
 > as effective!

Au contraire!  I used exactly this approach to monitor an antenna az/el
pedestal out at NASA White Sands Test Facility. We had the pedestal and a
battery powered clock in the video scene, and wrote a little VB application
to read the clock (since the hands are always in the same place, it's easy)
and generate a file that told when the pedestal moved.

For a more current application of "video capture for data acquisition"
consider the sundial on the Mars Rovers.

The real hangup you have to watch out for is limited resolution and contrast
issues. You're not going to read a panel of LCD displays or analog dials on
a 320x240 webcam.  If you have dials with big fat pointers (like aircraft
gauges) it works fairly well for trending.  The video scheme also works
fairly well for things like a manometer panel fed from a pitot rake.