Hi, I just wanted to give an update. I purchased the magnetic cat door as
the cat does not have a digital chip yet, he is still all analog! Although
he does have 20 digits. I have to say this quietly as Skink is sitting in
my lap, he will be visiting the vet on January 9th and will come home a
little lighter in the gonad department. I will get him chipped at the same
time, $25.00 more. In the long run I will probably get a microchip
operated door. I am not very worried at all about other cats with
magnetic collars in this area of town. We only seem to get the lowbrow
slumcats that have no collars. We mostly have businesses and old houses
divided into apartments. The typical landlord will not let a appartment
dweller cut holes for cat doors. My biggest worries are stray cats,
racoons, oppossums, and probably squirrels. Racoons I realy hate as they
have gotten into the big house and done a lot of damage. Well many thanks
for all the help with this issue. And happy holidays to everybody!
Tim laing
>
> Hello, well the cat problem has escalated. I opened the door this morning
> and there was a unfamiliar tom on the stairs who had our cat backed up by
> the window so he couldn't get to his accustomed cat bed. I caused some
> consternation on the part of the 2 cats, finally after some growling the
> tom bailed out the window which I promptly closed. This is the second time
> that I have seen the tom on the stairs and some things on the landing got
> broken.
> One of the guys on Neonixie-l pointed out some cat doors that work with
> a collar. Due to the situation with our cat and me having to spray
> Fabreze on the landing for the smell. I went and ordered a cat door
> that was pointed out to me on E-bay, it works with a special collar. So
> till that comes we will have to work out something with the cat on
> going in and out. Skink the cat is going to the vets for a neutering
> on the 9th of January, I will get him chipped at the same time and then
> I may look to upgrade the door. Chip operated doors run well over $100
> though.
> So I want to thank everybody for the ideas and the links to the door. I
> havn't had a cat that we let inside for well over 10 years so I havn't
> kept up on any of the doors etc for cats. All your ideas were a help
> and I appreciate them very much.
> Happy holidays to everybody!
> Tim Laing
>> Simple receiver tuned to harmonic would be easy.
>>
>> danial stocks wrote:
>>
>>>
>>>
>>> Yep the nonlinear junction detector is another interesting approach. I
>>> think the harmonic generation is possibly a less easy thing to detect
>>> than an on frequency passive resonator, although the harmonic method
>>> is also used in a number of systems.
>>> Dan
>>>
>>> >
>>> > > I don't think anyone has suggested a simple 'tag' which consists
>>> of just
>>> > > a coil with a diode in series. Could be a loop with detector, such
>>> as
>>> > > some of the cheapest RFID tags use. The interrogator is something
>>> > > driving a large coil [in this case just around the openint] and
>>> > > detecting the second harmonic generated by current flowing in the
>>> > > diode. I think it could be very simple but not proposing a design.
>>> > >
>>> > > Ed
>>> > >
>>> > > danial stocks wrote:
>>> > >
>>> > >>
>>> > >>
>>> > >> If you want to do something simpler, you could try a passive
>>> resonance
>>> > >> absorber - this is how some of those anti theft things in shops
>>> work -
>>> > >> have an oscillator sweeping a small frequency range - the tag on
>>> the
>>> > >> cat is a resonant LC circuit. When it is near the search coil,
>>> there
>>> > >> is a dip in te spectrum - basically the same idea as a grid dip
>>> meter.
>>> > >> This might be more sensitive than just a shorted loop. The
>>> oscillator
>>> > >> sweep will give immunity to random objects - something like a
>>> shorted
>>> > >> loop will absorb across the whole range - the sweep is wide enough
>>> > >> that thermal variations etc in the resonant circuit are accounted
>>> for
>>> > >> - youare just looking for an absorption dip anywhere in the range.
>>> > >> Shop sensors typically do this in the 6-8mhz range.
>>> > >> Dan
>>> > >>
>>> > >> >
>>> > >> > I work with RFID tags at work all the time, I hate those little
>>> > >> buggers,
>>> > >> > half the time they don't want to read on the pallets. Knowing
>>> the
>>> > >> typical
>>> > >> > cat I will have to be replacing them all the time. I think if I
>>> can
>>> > >> get a
>>> > >> > simple circuit to detect a shorted loop about 1.5-2 inches in
>>> diameter
>>> > >> I
>>> > >> > will be pretty well set. I just want to throw something
>>> together with
>>> > >> > parts I have on hand. The RFID is a good idea though, thank you
>>> for
>>> > >> > suggesting it.
>>> > >> > Tim Laing
>>> > >> > >
>>> > >> > > get an RFID reader. some RFID dev boards can be had for pretty
>>> > >> cheap. Put
>>> > >> > > the tag on the cat, door opens for the cat with the tag...
>>> > >> > > Dan
>>> > >> > >
>>> > >> > >>
>>> > >> > >> Hi, this is off topic but I know there are a lot of
>>> electronics
>>> > >> guys
>>> > >> > >> here.
>>> > >> > >> I posted this on Neonixie-L first. I also thought I would
>>> post
>>> > >> here as
>>> > >> > >> well. This cat door is for the black cat that was guarding
>>> my CRA
>>> > >> > >> skysweeper tube! I guess a automatic cat door would be on
>>> topic if
>>> > >> I
>>> > >> > >> used
>>> > >> > >> tubes. The tubes could sit under his cat bed and keep him
>>> warm. But
>>> > >> I
>>> > >> > >> think that transistors or an IC or two would be more
>>> practical.
>>> > >> Thanks
>>> > >> > >> guys.
>>> > >> > >> Tim Laing
>>> > >> > >>
>>> > >> > >> ---------------------------- Original Message
>>> > >> > >> ----------------------------
>>> > >> > >> Subject: Off topic Circuit for automatic cat door.
>>> > >> > >> From: [email protected]
>>> > >> > >> Date: Thu, December 20, 2012 3:04 am
>>> > >> > >> To: [email protected]
>>> > >> > >> Cc: [email protected]
>>> > >> > >>
>>> > >>
>>> --------------------------------------------------------------------------
>>> > >> > >>
>>> > >> > >> There are a lot of smart people on this group so I thought I
>>> > >> would ask
>>> > >> > >> for
>>> > >> > >> some help. We have a stray cat that we have adopted. He is an
>>> > >> indoor
>>> > >> > >> outdoor type of cat. My personal experience is if they
>>> started
>>> > >> outdoors
>>> > >> > >> they are very unhappy if you try to keep them in all the
>>> time.
>>> > >> Well the
>>> > >> > >> problem is there are some other strays that beat up on him
>>> and get
>>> > >> at
>>> > >> > >> his
>>> > >> > >> food. My temporary solution was to leave the window to our
>>> stair
>>> > >> landing
>>> > >> > >> open and Skink could jump up about 5 feet and get in through
>>> the
>>> > >> window.
>>> > >> > >> Then he could sleep on the landing if we were not home and
>>> eat as
>>> > >> well.
>>> > >> > >> Well we have two problems, 1) it is now pretty cold(The
>>> stairs
>>> > >> lead to
>>> > >> > >> our
>>> > >> > >> front door so that area is not heated.) 2) The big problem is
>>> I
>>> > >> came in
>>> > >> > >> tonight and the wild stray that has been going after Skink
>>> had him
>>> > >> > >> cornered on the landing. Needless to say I wasn't too happy,
>>> the
>>> > >> last
>>> > >> > >> thing I need is a tom spraying on the landing! And no, I am
>>> not
>>> > >> going
>>> > >> > >> to
>>> > >> > >> shoot the other cat as I live in town and I don't shoot cats
>>> etc.
>>> > >> > >> My idea was to make a automatic cat door that would open for
>>> only
>>> > >> one
>>> > >> > >> cat. I was thinking that if I made a cat collar out of light
>>> gauge
>>> > >> > >> copper wire with male and female spade connectors this would
>>> form a
>>> > >> > >> single turn shorted loop. (The wire would be light gauge so
>>> if he
>>> > >> got
>>> > >> > >> caught the wire would break.) The cat door would be a partly
>>> > >> formed with
>>> > >> > >> a square wood tube that the cat would enter with a solinoid
>>> > >> latched door
>>> > >> > >> at one end. On the outside of the wood cat tunnel I would
>>> wind some
>>> > >> > >> turns of copper wire that would be tied into an oscillator
>>> > >> circuit. The
>>> > >> > >> shorted turn would either kill the oscillator or shift its
>>> > >> frequency
>>> > >> > >> allowing the door to open.
>>> > >> > >> I can build just about anything electronic or mechanical and
>>> have
>>> > >> lots
>>> > >> > >> of parts on hand but I am not very skilled on scratch
>>> designed
>>> > >> circuits
>>> > >> > >> like this. Would somebody here be willing to help me with
>>> some
>>> > >> pointers.
>>> > >> > >> I can work from an hand drawn schematic. I should be able to
>>> supply
>>> > >> > >> power from a wall wort if needed.
>>> > >> > >> Thanks
>>> > >> > >> Tim Laing
>>> > >> > >>
>>> > >> > >>
>>> > >> > >>
>>> > >> > >>
>>> > >> > >>
>>> > >> > >> ------------------------------------
>>> > >> > >>
>>> > >> > >> Visit the TCA web page at: http://www.tubecollectors.org
>>> > >> > >>
>>> > >> > >> If you have questions about or problems with
>>> > >> > >> the TCA reflector, please contact the list manager
>>> > >> > >> Ron Lawrence directly at W4RON at carolina dot rr dot com
>>> > >> > >>
>>> > >> > >> Visit the TCA Tube Photo Gallery web page at:
>>> > >> > >> http://radioheaven.homestead.com/TCA.html
>>> > >> > >>
>>> > >> > >>
>>> > >> > >>
>>> > >> > >> Yahoo! Groups Links
>>> > >> > >>
>>> > >> > >>
>>> > >> > >>
>>> > >> > >
>>> > >> >
>>> > >> >
>>> > >> >
>>> > >> >
>>> > >> > ------------------------------------
>>> > >> >
>>> > >> > Visit the TCA web page at: http://www.tubecollectors.org
>>> > >> >
>>> > >> > If you have questions about or problems with
>>> > >> > the TCA reflector, please contact the list manager
>>> > >> > Ron Lawrence directly at W4RON at carolina dot rr dot com
>>> > >> >
>>> > >> > Visit the TCA Tube Photo Gallery web page at:
>>> > >> > http://radioheaven.homestead.com/TCA.html
>>> > >> >
>>> > >> >
>>> > >> >
>>> > >> > Yahoo! Groups Links
>>> > >> >
>>> > >> >
>>> > >> >
>>> > >>
>>> > >
>>> > >
>>> >
>>> >
>>> >
>>> >
>>> > ------------------------------------
>>> >
>>> > Visit the TCA web page at: http://www.tubecollectors.org
>>> >
>>> > If you have questions about or problems with
>>> > the TCA reflector, please contact the list manager
>>> > Ron Lawrence directly at W4RON at carolina dot rr dot com
>>> >
>>> > Visit the TCA Tube Photo Gallery web page at:
>>> > http://radioheaven.homestead.com/TCA.html
>>> >
>>> >
>>> >
>>> > Yahoo! Groups Links
>>> >
>>> >
>>> >
>>>
>>
>>
>
>
>
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