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  • badweasel commented on landmanr's instructable RFID Cat Door2 months ago
    RFID Cat Door

    I have the HIGH TECH Power Pet electronic door. I am willing to share my work. I just did a reworking of the door a couple of weeks ago. So I can include those fixes. My new system has an LED that shows the status of where the dog is (green for outside, blue for inside). And the new sensor the dog wears is very cheap ($1) requires no batteries, and is smaller than a normal dog tag. It's a dog tag RFID.I'm not sure it belongs here on instructable but maybe on my own blog. It'll take me a little while to write it up though.

    It's not going to work with your pet's microchip. There are several reasons why not. But basically, the placement under the skin and orientation of that chip vs the orientation of the reader means your pet would have to be trained to rub up against the reader in a very specific way. If you could train your dog to do that you wouldn't need an rfid reader. You could just train them to use the toilet or to use a level or button to open the door. So forget about the microchip they already have. It won't work. In fact with my dog door the rfid tag has to hang down from her neck in a specific orientation or it won't work. RFID sensors read like this | | not like this – |, where the two lines represent the orientation of the tag and the reader coil. Off angle like this / | won't ...

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    It's not going to work with your pet's microchip. There are several reasons why not. But basically, the placement under the skin and orientation of that chip vs the orientation of the reader means your pet would have to be trained to rub up against the reader in a very specific way. If you could train your dog to do that you wouldn't need an rfid reader. You could just train them to use the toilet or to use a level or button to open the door. So forget about the microchip they already have. It won't work. In fact with my dog door the rfid tag has to hang down from her neck in a specific orientation or it won't work. RFID sensors read like this | | not like this – |, where the two lines represent the orientation of the tag and the reader coil. Off angle like this / | won't work very well either. This is why when you get to work you have to lay your security card flat against the reader. When you have coil alignment the read distance will be at max it can be. Turn it off axis slightly and the read distance decreases exponentially based on how off axis it is.

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  • badweasel commented on landmanr's instructable RFID Cat Door3 months ago
    RFID Cat Door

    My antenna goes around the entire tunnel the dog travels through to go in and out. When the dog passes thru it reads the tag, but only if the tag is aligned with the antenna. So the rfid tag had to be fixed to her collar so that when hanging down naturally it faces forward. When I properly tuned the antenna and removed noise in my system I got about 9-12 inches (not cm) from the center axis. In other words it would read the tag when the dog was entering the tunnel, before she was in the middle of the antenna. Which is where I needed it to work. Noise was a problem when I used a power supply instead of a battery. I fixed this by grounding my system to the actual ground. Recently I've been having problems with my system again. I think antennas are tricky and fragile.

    The embedded tag probably won't work. For one the 3d alignment of the tag to the antenna is significant. For another it might not be the same frequency. An example of the alignment is imagine you have a loop antenna that is like a circle in front of you and you turn your tag so that it's 90 degrees off from that alignment and pass it thru the loop - it might not read at all. But turn it so that it's flat against that circle and it will read much better and farther away. The tag in your cat isn't going to match that alignment.

    I actually did get mine working. My RIFD reader can report back with the .. um.. frequency?.. of the antenna. You send a MOF (measure operating frequency?) command to it and it reports back. So used that to get my antenna sort of close (not really very close) just by guessing on the # of winds. Then I bought a variety pack of capacitors and my RFID reader also has a place to insert adjustment capacitors to 'tune' the antenna. So with that I was able to get it fairly close to 125. It worked for a while. It's not been working well lately. So I checked and the tape I used to hold the winds tight had broken down. I've fixed that but at the moment I'm not getting any readings when the tag is near.I also had a lot of problems with noise. The power supply I'm using is noisy and it ke...

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    I actually did get mine working. My RIFD reader can report back with the .. um.. frequency?.. of the antenna. You send a MOF (measure operating frequency?) command to it and it reports back. So used that to get my antenna sort of close (not really very close) just by guessing on the # of winds. Then I bought a variety pack of capacitors and my RFID reader also has a place to insert adjustment capacitors to 'tune' the antenna. So with that I was able to get it fairly close to 125. It worked for a while. It's not been working well lately. So I checked and the tape I used to hold the winds tight had broken down. I've fixed that but at the moment I'm not getting any readings when the tag is near.I also had a lot of problems with noise. The power supply I'm using is noisy and it kept it from reading tags. My fix was to ground the circuit to actual ground.. like metal in the house frame.My addition now is that I have a micro PIR sensor on the inside of the door, and one inside the tunnel (outside the door). I'm using the timing and cadence of those triggers to determine if the dog actually goes out the door. If so then I watch the outside one for a few minutes to let her in even without the rfid tag. However if she stayed out too long, or triggered the outside PIR without coming back in, then it would revert back to requiring RFID to enter.

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  • badweasel commented on landmanr's instructable RFID cat door1 year ago
    RFID cat door

    Did you ever figure it out? I'm having the same issue where I need a larger antenna, except that I'm not getting anything at all with mine.

    I'm trying to build this project except that I already have an electronic dog door mechanism. The door I have uses an ultrasonic collar to trigger the door and it's super finicky, the dog collar is large for a small dog, and the batteries are proprietary and ultra expensive. So my goal is to hack the door I already have to use RFID instead of ultrasonic.The exiting through the door part is easy. I'm using a micro PIR sensor for that and it works great. The coming back in will need the RFID and the reader and antenna I have is very short range. I belive it's the same one used in this project. I have to place the tag right on the antenna. Although to be fair I have been powering it over USB. I tried to build my own antenna using the same sized wire and method shown here (10x10 inch s...

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    I'm trying to build this project except that I already have an electronic dog door mechanism. The door I have uses an ultrasonic collar to trigger the door and it's super finicky, the dog collar is large for a small dog, and the batteries are proprietary and ultra expensive. So my goal is to hack the door I already have to use RFID instead of ultrasonic.The exiting through the door part is easy. I'm using a micro PIR sensor for that and it works great. The coming back in will need the RFID and the reader and antenna I have is very short range. I belive it's the same one used in this project. I have to place the tag right on the antenna. Although to be fair I have been powering it over USB. I tried to build my own antenna using the same sized wire and method shown here (10x10 inch square at 24 winds) but with that one it doesn't read anything at all. I also don't have equiment to measure inductance (that I know of).I've looked at the microchip pdf but it's over my head. I wish I could just buy a large antenna that I could use that would read the dog tag at the distance I need.

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