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Monday, 10 October 2011

GPS feline tracker.

Say hello to Ash. Isn't that a nice collar on him?

Ash is my Russian Blue cat, and loves his neighbourhood adventures. Regularly off for hours on end, he could end up in who knows what garden, possibly halfway down the street. After endless such adventures, I figured it was time to find out where he really was going.

GPS is of course the way to go, so I looked around for a tracker I could attach to him. Turns out that all the ones commercially available are far too large. A common one available on ebay is about the size of a matchbox - too large for a cat. All other pet trackers are made for dogs, it seems.

So it was time to roll my own.



A tracker has pretty much only one way to attach to a cat - on the collar. That means small and light is essential - Ash needs to be able to ignore the collar and its attachments. So I needed to find the smallest stuff I could get.

The most important part of tracking is the GPS to actually get location. Nowadays there are a lot of GPS modules around. I ended up picking the MiniMod from Sparkfun - at only 4x1.5cm, it's a super tiny module, not much wider that a cat collar, and not overly long. With a built in (tiny!) antenna and serial output, it has everything I need.

Next, the signal from the GPS needs to be sent somewhere. Live transmission was out of the question - there arent any GSM modules small enough, and no other radio would have the range I needed, even at that size. So local logging was the way to go. After thinking up a few ideas about small microcontrollers and flash chips, I discovered the Openlog. At under 2cm long, and 1.5cm wide, this tiny module consists of not much more than an AVR and a micro sd slot. It works by simply logging whatever serial data is fed to it onto files on the SD card.

All I had to do was connect the GPS serial output into the Openlog, give them both power, and Bingo, a complete tracking solution!

Of course the modules also need power, which must be capable of attaching to the collar. AA's and AAA's were out - way too big. A while back I picked up one of those tiny LCD photo keychains, for something like $7. And inside had exactly what I needed, a small Lithium Polymer battery that was a bit smaller than the GPS module, and gave 3.7 volts.

And that's all it took.

Battery, OpenLog and GPS are all strapped to the collar with cable ties and duct tape, small wire-wrap wire connects them all together, with a small connector for the battery so I can charge it. Attach to the cat, and off he goes prowling the neighbourhood, having his location merrily logged to SD for about 2 hours before the battery dies.

He's not a particularly fussy cat, and he lets me attach the collar to him without a struggle, and it doesn't seem to bother him at all. So far it's also been immune to scratching and other abuse you'd expect. It's not waterproof though, I'll only attach it on a dry day.

Once he comes back, all I have is a load of NMEA data on the SD card. It's not very human parseable, and I'm not good at converting lat/long data into actual houses around here.

So it's Python to the rescue! A quick script converts NMEA data into KML, suitable for Google earth/maps, and up pops a full track of where he is. A link to the (awfully coded) script.


I'm actually quite surprised how far he roams. Rather than just the houses on either side or right across the street, he ends up quite a few houses away, and almost to the next street across. That probably explains why he often won't come when called, he's just too far away. At least he enjoys a wide territory to roam...



38 comments:

  1. Very cool, almost makes me want to get a cat.

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  2. The traverse of the swimming pool (lower left) is interesting (I know...connecting two points etc. etc. but the visual of Ash swimming furiously just to mess with you is a good one).

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  3. It's not the transversion that interests me, but it's the one datapoint that is inside the pool in the lower left corner :)

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  4. This sounds perfect for keeping track of family members..... Trick now to get this under there skin or attached to them somehow... this could almost be the next step in some massive corporations global scheme for world domination. Illumiati style...
    tell me who do you work for, oh wait I already know! 0_o

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  5. Post some more maps, does your cat walk the same path every day? :)

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  6. I immediately remembered this:
    http://en.wikipedia.org/wiki/L%C3%A9vy_flight

    Your cat is not only walking around, he's moving in a fractal trajectory ,)

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  7. Very cool. I've often wondered where all my cat visits on her outings.
    Pretty clever and determined way of finding out you have developed there!

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  8. I wanted to do something like this with my dogs for a while now.
    Would you be willing to provide a link to your Python script that converts NMEA data to KML?

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  9. I've now included a link to the python script. It's pretty awful, but works. By default, integrates 10 samples to 1, and ignores samples where < 5 satellites are visible. Edit if you want to change.

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  10. I was wondering, is there any decent alternative to that GPS module ?! i would really like to build similar device for my cat..

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  12. That's definitely cool. I would love to have one of those GPS and put it in my car. It'll be a good addition to its features.

    gps tracking

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  13. @Dennis Ray Nestor Jr.
    Here you have 720p camera recorder, which is perfect for that:
    http://www.hobbyking.com/hobbyking/store/__17200__HD_Wing_Camera_1280x720p_30fps_5MP_CMOS.html

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  14. GPS tracking devices are very common nowadays. They can be used to track a person, a pet or a car. I have installed a GPS tracking device to my newly bought used lincoln mkx car. It's leading me the right direction. That's what I love about GPS.

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  15. I also have a GPS tracker installed in my car. I put this in the car which I just bought from advantage toyota recently. It's a cool device by Garmin. GPS is a useful device to track the right location of a place or a thing.

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  16. I bought a car from an audi dealer who gave me a better and very great deal. I was also convinced to put a GPS device for additional safety.

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  17. When I bought a car from one of the Toyota Dealers NY, I also decided to put extra accessories and equipment to maximize its functionality. I installed car camera and gps. They made my car more compelling and highly functional.

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  18. can you link me to the GPS you're talking about? I cant find it on sparkfun

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  19. Same for me, and i have two cats!!!

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  20. I am also very interested in your gps!! Could you give me some more information please?? My cat is been hijaked for 9 times now!! I need to follow him in order to find the offender!

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  21. Have been looking for something like this for a while now,love your design. Is there any chance for the less techno savvy people you could include some detailed instructions/photos for people to recreate your great device. I would appreciate it.

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  22. For the even less technological, you wouldn't consider making one would you? Happy to pay, as like you haven't been able to find anything to buy that I think our cats would tolerate for more than a few seconds! Many thanks, Kirsty

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  23. Contacted Sparkfun for another solution and they suggest another GPS receiver, the GP2106 the same lipo battery and open log data recorder . but i have to include a gps evaluation chip to bypass the voltage downfall from 3.7volt to 1.8volt. They all should fit on "Belle" small cat collar. I'm building one right now and ill be back soon to show photos.
    JP

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    Replies
    1. any chance of you selling the collars? :D
      I always fear my cat will escape and ill never find him again...

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    3. same as the above, I've been looking all over for a gps locator/tracker small enough for cats and there doesn't seem to be any! please let me know... thank you

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  24. Great, this is very funy and nice. Do you mind to provide rference product and shema?
    Good work
    Cheers

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  25. Hi :)
    Please, can someone create a list of components necessary to build this collar?

    Excuse me but I am not an expert and I am in difficulties.
    Thank You very much

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  27. According to Desmond Morris in "Catwatching", the average tom roams 175 acres. The average female, 12.5. So your boy is normal. But that street!

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  28. It’s great to link the technology with the animals featuring the crystal path while showing the remarkable tale. The world has become a very small place to live in while the rest are busy in inventing the new technology at every moment. GPS positioning is a boon to show simply the evidences and nothing else…A lot of results dragged out may or may not be a positive output for every individual.
    FootPrint Security

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  29. I think GPSBabel would do the NMEA to KML conversion too. One of the cool options I saw when I was working on a previous project, was that you could set the 'height' of the line to be the speed. So it's easy to see how quickly to see how fast you (or your cat in this case) was moving at the time.

    I'd love to make one of these for me cat too, but it seems like the GPS modules have moved on since. I'd love to be able to transmit the NMEA data instead of storing it, so that I can find my cat too :-)

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  30. Hello,
    Greate, nice and funy tuto. Could you list us the part you used for your project? I am particularely thinking about the GPS.
    Cheers

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    1. The GPS module was from Sparkfun, but is not sold any more. You will need to find an alternative. The SD logger is the openlog, plenty of info online for it.

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    2. it was called the minimod: sparkfun dot com/products/8416 an alternative could be this: sparkfun dot com/products/11058

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  31. Have you seen radios like these? http://www.argentdata.com/products/radios.html

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