From: medin@catbyte.b11.ingr.com (Dave Medin)
Subject: Re: DC Shock
Reply-To: medin@catbyte.b11.ingr.com
Organization: Intergraph Corporation, Huntsville AL
Date: Tue, 14 Apr 1992 21:46:03 GMT

In article <227-PCNews-120beta@hacktic.nl>, bill@hacktic.nl (Bill Squire) writes:
|> berger@atropa (Mike Berger @ University of Illinois at Urbana) once wrote....
|> >dino@inqmind.bison.mb.ca (Tony stewart) writes:
|> >>jon@sparcplug.et.iupui.EDU (Jon Burgoyne) writes:
|> >
|> >>> I'm looking for a small circuit that could provide a shock to my dog.  This i
|> >>> to build a collar similiar to the invisible fence product.  I believe they us
|> >>> a 22.5v bat.
|> >>> 
|> >>> The RF part I can probably struggle through but producing a shock was not
|> >>> something they taught us in school.
|> 
|> >Why does anybody want to help this guy torture his dog?
|> 
|>         I agree with the above and to states and countries that have banned
|> these things.  A much nicer to the dog and probably as effective way is to
|> produce a fairly loud 15 to 20kHz tone right at the dog.  I think that will
|> give him the message!  Shocker things are easy to build, but as long as
|> this application is in discussion, I'll refrain from giving any ideas!

Give me a break! I suppose you don't swat your dog with a newspaper
either when it poops in the house. The idea is to supply an
unpleasant sensation to the dog when it disobeys ONLY for the sake
of discipline. My neighbor has such an "invisible fence," and their
dog was no worse off after having been trained on it. It no longer
strays from the yard as it did and seems to be mentally well-adjusted.
We're not talking burning, high-energy shocks here...

The shock generator can be made easily by using an inductor for
flyback. With one side of the inductor tied to V+, the other
end is switched momentarily to ground, building a current ramp
through the inductor. Then, the switched end is let loose, and the
inductor, in trying to maintain current flow, raises the
voltage on the switched node to the point where:

	1. All the energy is stored in inter-turn capacitance
	and/or dissipated in losses.

	2. Is dissipated through a load. In this case, it provides
	a shock.

The inductor is chosen so that it can store the energy required for
a small, unpleasant shock without saturation. The switch pulse
width is chosen such that the current through the inductor
gets to the point where the proper amount of energy is stored.

A shortcut (which provided some practical jokes in my high school
days) was to use a small SPDT reed relay (the mechanical type) where the
coil current was switched through the normally closed set
of relay contacts. This would cause the relay to oscillate, and
the switched end of the relay coil to develop several hundred
volts off a 9 volt battery. The relay will quickly wear out if
used continuously, so power it only long enough to deliver a brief shock.

-- 
------------------------------------------------------------------------
     Dave Medin				Voice: (205) 730-5812 (w)
  Intergraph Corp.			       (205) 837-1174 (h)
     M/S CR1104
Huntsville, AL 35894-0001	Internet: medin@catbyte.b11.ingr.com

   *********Everywhere You Look...(at least around my office)***********

       *The opinions here are strictly my own (or those of my machine)
From: nt@otter.hpl.hp.com (Nicolas Tripon)
Date: Fri, 10 Apr 1992 09:49:28 GMT
Subject: oversampling & bitstream
Organization: Hewlett-Packard Laboratories, Bristol, UK.