Hi Tim Just in case you didn't know, exactly this device has been built already and is commercially available. It uses the subcutaneously implanted RFID 'microchip' that is used worldwide for identifying animals, and will let in your cat(s) and only yours (you program which cat's to allow).
They're great because they're fool proof, and do not rely on a collar that could be lost or pose a strangulation hazard to for the cat. I understand you may rather build than buy an off-the-shelf product, but maybe it can give you a few pointers? Here's a sample listing (not affiliated etc.) http://tinyurl.com/ct6abq5 HTH Ray -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: 20 December 2012 08:04 To: [email protected] Cc: [email protected] Subject: [neonixie-l] Off topic Circuit for automatic cat door. 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 -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
