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Re: Wireless ON/OFF for Tesla Coils- anyone done it?
From: Mike Harrison[SMTP:wwl-at-netcomuk.co.uk]
Reply To: wwl-at-netcomuk.co.uk
Sent: Tuesday, November 04, 1997 7:54 AM
To: Tesla List
Subject: Re: Wireless ON/OFF for Tesla Coils- anyone done it?
O>
>
>The other day, I was thinking back to a Richard Quick post, where Richard
>described the 60Hz house ground "The last line of defense" or something
>like that. He was refering to situations where the discharge from the
>secondary could strike the primary, and the operator console, potentially
>subjecting the operator to primary circuit currents.
>
>What I am wondering is anyone on the list has tried switching a coil on
>and off by remote, i.e. no wires or conductors connecting the user to any
>part of the system. I was thinking of imploying a simple infra red
>system, whereby presence a specific infrared signal (from a tv-like
>remote control) would be used to switch power on through a suitably heavy
>relay in series with the normal SPST manual key switch. Pressing the
>remote button and _holding_ would fire the coil, and releasing the button
>would cause immediate cutting of power.
>
>Of course the receiver and relay circuit would have to be nearly fault
>proof, to avoid having a coil stuck in the on position for any reason,
>but this can certainly be safe guarded against by a good design.
>
>Any comments and suggestions would be appreciated.
>
You'd have to be very careful - IR detectors are very sensitive, and
the RF from a TC would be hard to keep out - you'd need to sheild RF
without affecting the optical performance. Also the spark flashes may
well be picked up by the detector - I'd guess they have a fair amount
of IR content.
One way to avoid both problems, at the expense of freedom of movement,
would be to use a fibre optic cable - the detector could be well
screened, with the fibre coming in through a nice small hole (or tube
if you really wanted max shielding). 1mm polymer fibre is good for
5-10mm and is dirt cheap.
One other possibility, though, may be to have the receiver (IR or RF)
sync'd to the AC line, so it only listened when it knows that the coil
won't be firing. Maybe a UHF car-alarm type system?