Re: Of Mice and HV (fwd)

["High Voltage list" <hvlist@xxxxxxxxxx>]

Original poster: Steven Roys <sroys@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Thu, 13 Apr 2006 20:02:05 +0200
From: Finn Hammer <f-h@xxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Of Mice and HV (fwd)

Great idea!

I think animals will be able to sense the E-field from charged plates 
far away, so they will be reluctant to enter between them.

You probably have to build  some sort of  sensor to verify that the 
mouse is lined up between the electrodes. When it is in position, squirt 
liquid conductor on the critter, and gate SCR.

Cheers, Finn Hammer

High Voltage list wrote:

>Original poster: Steven Roys <sroys@xxxxxxxxxx>
>
>
>
>---------- Forwarded message ----------
>Date: Tue, 11 Apr 2006 07:20:03 +0930
>From: Matthew Smith <matt@xxxxxxxxxx>
>To: High Voltage list <hvlist@xxxxxxxxxx>
>Subject: Of Mice and HV
>
>Greetings All
>
>CONTENT WARNING: If you are distressed by nasty things happening to
>vermin (small furry creatures to those not infested with them), please
>do not read any further.
>
>They don't make 'em like they used to!  Our house, completed just over
>two years ago (actually not completed, but that's another story!)
>appears to have been built to accommodate rodents just as comfortably as
>humans.
>
>Snap traps have proved anything but reliable (bait gone, trap still set)
>and when they do operate, frequently kill in an unclean manner.
>
>So, I have decided to build an electric mousetrap.  Idea is simple:
>mouse enters trap and has to pass through a narrow gap between two
>aluminium plates arranged in a V.  (Mouse enters the larger part of the
>V.)  One plate is fixed, the other against light spring tension so that
>the subject has to push between the two plates to get to the bait.
>
>Plates are connected to a charged capacitor.  Charging will be from a
>PWM supply driven by a microcontroller which stops when capacitor
>voltage reaches an upper threshold and starts again once it has
>discharged (mostly through the feedback voltage divider) down to a
>minimum voltage.  The idea being that this device is battery-operated
>and tries to save power.
>
>Does anyone have any idea what minimum voltage I would need to apply to
>guarantee fatal fibrillation?
>
>I had considered powering from a disposable camera supply (no
>microcontroller - simply pulse the start button when the neon goes out)
>but, whilst photoflash capacitors can give us a ghastly bite, is the
>300V or so enough to take out a mouse in its insulating fur coat?  I've
>serviced equipment before where mice have gone in a mains (240V) PSU and
>have blown the fuses but am still unsure about the certainty of a clean
>kill.
>
>Once I've got this idea working, I want to motorise it so that the
>defunct rodent can be cleared from the plates and the trap be readied
>for another "client".
>
>Cheers
>
>M
>
>  
>