Re: Proximity sensor for RSG

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

Original poster: "Matthew Smith by way of Terry Fritz <teslalist-at-qwest-dot-net>" <matt-at-kbc-dot-net.au>

Hi Marco

>I need help in choosing the right proximity sensor: capacitive,
>inductive or magnetic? What will work? Anybody with experience on this?

I would agree with Jim that optical is probably the best way to go. Does 
the motor of your gap have a fan at the other end?  If it does, counting 
one of the fan blades will get you more physical distance from the sparks 
and a fan cowl gives you an instant mounting bracket ;-)

When we're in the optical domain, we can move the sensitive electronics 
even further away from the sparks - optical fibre.

Another good noise-immunity technique is to use an infrared LED driven by a 
555 or somesuch to about 38KHz, then detected by something like a Sharp 
IS1U60 - these are used to detect TV remote controls and the like.  These 
devices are fairly cheap and tend to ignore anything outside of their 
fairly narrow frequency range.  The output is 5V logic, IIRC.

Old dot matrix printers can yield suitable sensors (simple reflective 
devices) for cheap/free experimentation.

Hope something here is of use...

Cheers

M


-- 
Matthew Smith
IT Consultant - KBC, South Australia
KBC Web Site    http://www.kbc-dot-net.au
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