LIGHTNING DETECTOR

[rob g]

Elektor newsletter this week announces the first lightning sensor IC which detects lightning up to 40 km away. The world needs a cheap device which gives early warning of mains related arcing/corona in the home. The average homeowner finds this type of arcing audible but very hard to pinpoint.
` I looked at designing a similar device to detect small insulator breakdowns in pulsed electric fences used to manage cattle and this IC might save me some effort. Any other applications?

[grumbleduke]

My $4.75 kitchen radio tuned to medium wave dectects lightning 100 miles away and the odd newsflash too.

Richard

[rob g]

Faced with suspected mains-related arcing, the first choice is of course a transistor radio, but if noise from the arc is swamped by ambient wideband noise, the fringing ellect of a pinhole aperture in the screen surrounding a small electric field detector might well be designed to have the required directional properties.
Transistor radios cannot detect insulator breakdowns in pulsed electric fences because the pulse, of typically 30-60 joules, swamps the weak radiation from an insulator arci. Again either a waveguide-below-cutoff or a pinhole antenna might have the required directional pattern. Possibly in tandem with an acoustic detector fittd with a parabolic reflector?

[rob g]

Since my post of 5 MAY , I continue to design a supersonic receiver capable of locating electric arcs to within a few centimetres. It will be used to locate nascent breakdowns on electric fence lines, but might be useful also in locating arcs in domestic appliances.
M Marc Gerin’s anemometer design in the June Elektor issue might be adapted to this purpose by using a supersonic diode (http://phys.org/news/2011-07-one-way-transmission.html) as an acoustic charge pump with the dynamic pitot tube providing some directionality. I am struggling to estimate the the minimum forward and maximum reverse pressures in the pitot line under real life conditions. Has any reader looked at these devices against the usual piezoelectric detectors?

[rob g]

I doubt that "Tapir" can detect power line breakdowns or sparking from pulsed electric fence energisers-The noise on power lines swamps the nascent breakdown of insulators. But AND-ing the ultraviolet/acoustic/EM spectra might.

[rob g]

This project now abandoned due to compex nature of the required dual acoustic./electric probe, Calibration easy with a gas igniter but implementation too hard, Now switching to a light-emitting capacitor hooked to the fence hot wire as a beacon for nightime surveillance by the farmer.