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Ginger cat detector

Discussion in 'Embedded' started by Stephen Pelc, Apr 4, 2008.

  1. Stephen Pelc

    Stephen Pelc Guest

    I was looking for a new demo application and we've done model
    trains before. As usual, a real-life problem, this one involving
    building management, presented itself.

    We have two cats in the house. We have a very fat black cat
    and a semi-wild skinny black and white one. A very hansdome
    ginger tom has taken to coming through the cat flap, feeding
    itself and spraying, which is the problem.

    Naturally this happens at night when the humans are asleep.
    Collars and magnetic cat-flaps are not an option. Can anyone
    suggest an inexpensive and reliable method of determining
    which cat came through the cat-flap? I really don't want to
    implement the counter-measures until this problem is solved!
    Our cats are not chipped.


    Stephen Pelc,
    MicroProcessor Engineering Ltd - More Real, Less Time
    133 Hill Lane, Southampton SO15 5AF, England
    tel: +44 (0)23 8063 1441, fax: +44 (0)23 8033 9691
    web: http://www.mpeforth.com - free VFX Forth downloads
    Stephen Pelc, Apr 4, 2008
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  2. Stephen Pelc

    larwe Guest

    This is a solved problem with a COTS solution! <http://
    larwe, Apr 4, 2008
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  3. Stephen Pelc

    Dave Guest

    Nice problem, I was thinking of two sprung flaps mounted vertically above
    one another. The cat's enter the top and the skinny one will walk straight
    across into the house. The fat one will fall through the first and second
    flaps and then through into the house. The ginger one will fall through the
    first but not the second and from there can only go back out of the house!
    Just need to tune the spring rates.

    I suppose an electronic version would be to have some mass measurement that
    determines which cat it is then opens the appropriate flap to the house or
    back outside.
    Dave, Apr 4, 2008
  4. Stephen Pelc

    larwe Guest

    Cats don't care for funhouse rides; I think this mechanism will train
    them all to just stand outside and mew :)
    larwe, Apr 4, 2008
  5. Put rubber booties on your cats and electrify the floor. Ginger cat
    will only visit once!

    Chris Eilbeck, Apr 4, 2008
  6. Stephen Pelc

    larwe Guest

    I gotta say - the replies in this thread are the very soul and
    definition of what engineering is all about!
    larwe, Apr 4, 2008
  7. Stephen Pelc

    larwe Guest

    Typically between $20 and $60 depending on how much your local vet
    feels his time is worth. Almost all animals that have been adopted
    from shelters will be supplied with the chip preinstalled.
    Readers are given gratis to animal shelters, but there is no unified
    standard (!!!!!!) so several readers are required. Fortunately there
    are open-source projects <http://maxmicrochip.com/>
    larwe, Apr 4, 2008
  8. On that sort of crappy breadboard you need 5 just to be sure one of
    them makes contact :)
    John Devereux, Apr 4, 2008
  9. Stephen Pelc

    Lanarcam Guest

    Use the flap as a trigger for a camera, send the photo
    to a PC where a program will analyse the color spectrum,
    release a fake mechanical mouse that will lead the
    ginger cat to the terrier and hope that the cat's
    owner is not a lawyer.
    Lanarcam, Apr 4, 2008
  10. Weighing the cats is a simple and obvious solution and if it works
    could be very reliable. It depends on how similar the cats are in
    weight and how much they vary day to day.

    ISTR hearing that certain parole offices in the States measure
    galvanic skin response to identify offenders. It could conceivably
    be used on the cat's paws although I suspect it would vary far too
    much to be useful with wet and/or muddy feet.

    Sample the cat's miaow and run it through an FFT. I must admit
    that I have never actually studied the finer points of noises made
    by cats, but I wouldn't be surprised if you found that each cat's
    miaow had a distinctive signature. Of course this depends on the
    cat miaowing in the first place but in my experience that is rarely
    a problem when they want to be let in.
    Andrew Smallshaw, Apr 4, 2008
  11. Stephen Pelc

    Terryc Guest

    That is ecause they wanted to be let in through the window and not the
    door. BTDT.
    Terryc, Apr 5, 2008
  12. Stephen Pelc

    Al Guest

    If the ginger cat is a stray, catch it. Put a collar on it with the
    magnet or else an RFID tag. Install a gadget in the cat door that locks
    it when the ginger cat approaches and either the magnet or the tag
    activates it.

    Al, Apr 5, 2008
  13. Stephen Pelc

    CBFalconer Guest

    This makes sense, but is upside down. The ginger-cat-owner is
    likely to remove such strange apparations as a new collar. Collar
    your beasts, and give them permission to enter.
    CBFalconer, Apr 5, 2008
  14. Stephen Pelc

    Al Guest

    A stray cat belongs to no one! There is no owner.

    Al, Apr 5, 2008
  15. Get a water-based fluorescent ink marking pen (kid's toy "spy pens" are
    ideal) and mark your cats' scalps. A photodetector and a small UV light
    source operate the flap latch, or disable the countermeasure (water

    Gene S. Berkowitz, Apr 5, 2008
  16. Stephen Pelc

    CBFalconer Guest

    You are an innocent in the ways of cats. They own humans, not the
    CBFalconer, Apr 6, 2008
  17. Stephen Pelc

    Al Guest

    Mea culpa! Yes, I have been owned by cats in the past...and by dogs.

    Al, Apr 6, 2008
  18. I would go for a combined wetware and hardware solution. Install
    a button switch by the cat-flap, and train your cats to push
    the button to unlock the cat-flap. It should not be too hard
    to train the cats to do that, search YouTube for cat training
    and you'll find plenty of material I'm sure.
    Pertti Kellomäki, Apr 7, 2008
  19. Stephen Pelc

    Ray Haddad Guest

    Not since the Finland Famine struck.
    Ray Haddad, Apr 8, 2008
  20. Stephen Pelc

    Lanarcam Guest

    CBFalconer a écrit :
    In fact, it should be possible to achieve it
    if you train your cats *not* to do push the
    Lanarcam, Apr 8, 2008
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