🚀 go-pugleaf

In sci.electronics.design Dale <ewgeneral@yahoo.com> wrote:
> Hi everyone out there.
> 
> Im looking at detecting failure of HPS street lamps where say you have
> up to 20 lamps on a particular circuit. Im only interested in knowing
> that one or more lamps are in failure state (i.e. from the moment they
> start to go through their on-off cycle)
> 
> (If anyone has got ideas on when a particular lamp has failed, via a
> single feeder circuit, of course I would be very interested, even
> maybe have a job for you!!! ;)

Finding a particular failed lamp is trivial.

PIC, and a powerline modemm.

Getting the cost down is the interesting bit.

Measuring the average power ripple in the 0.5Hz (or whatever) band may 
work for 20 lamps, how many lamps it will work for without false triggering
will depend on the normal amount of noise in the power draw at those
frequencies.
This would need little more than a couple of A/Ds, some software, and a
PIC, along with a current transformer to measure the current.

Then again, if you'r putting up a lot of lights, there may be better ways.
An little mains driven oscillator that squeels at a few Khz at a well 
defined frequency when the bulb is not lit would probably work well for
lots more lamps.


-- 
http://inquisitor.i.am/    |  mailto:inquisitor@i.am |             Ian Stirling.
---------------------------+-------------------------+--------------------------
He had been eight years upon a project for extracting sunbeams out of cucumbers,
which were to be put in vials hermetically sealed, and let out to warm the air
in raw inclement summers.  -- Jonathan Swift, "Gulliver's Travels" (1726)