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Topic: Indoor cat locator (Read 17152 times) previous topic - next topic

Indoor cat locator

For a while now I have been thinking about creating some kind of indoor cat location system that would be used to prevent my cat from walking on the kitchen table and a few other places. The problem with cats is they only obey rules when you are around and can see them. Once you go out or even to another room the do wherever they like.

There are a few ways of keeping your cat off the table and the only one proven successful is getting rid of the table altogether :) There are a few other but as they use motion sensors they would also be triggered by me. Personally I love the Blender Defender ( http://www.plasma2002.com/blenderdefender/ ) but it is too noisy and depends on motion detection.

My first idea is to put a collar around my cat's neck and have it carry a small 868MHz/2.4GHz transceiver and a CR2032 battery to power it up. A few receivers located in the corners could give me approximate position by signal strength analysis. Then I could set forbidden zones and trigger some kind of either noise or flash to teach the cat to keep off my shelves and tables :)

Another idea is to use a web cam with an IR pass filter installed on its lens and then have the cat carry a flashing IR LED. I have a small ARM Linux box ( NSLU2 ) which I could use for that.

I am open to any suggestions as I would really like to get it done. I do not want to use a cam and video processing for this.

Re: Indoor cat locator

Reply #1 –
If cell phones are really bad for children, then wouldn't it be bad for your cat to wear a microwave transmitter?  i.e., the IR solution might be safer.

What about ultrasonic radar?  I suppose that's still a form of image processing, even if it isn't video.

Re: Indoor cat locator

Reply #2 –
Quote
Another idea is to use a web cam with an IR pass filter installed on its lens and then have the cat carry a flashing IR LED. I have a small ARM Linux box ( NSLU2 ) which I could use for that.

I'd start here too, maybe using another IR LED also as a simpler IR detector. It seems like signal strength analysis could be complicated to get right in a confined space over short distances, but I don't speak from experience or anything.
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Re: Indoor cat locator

Reply #3 –
There is an other (proven to work) option: get rid of the cat ;)

You could use the sensor built into the wiimote to track IR signals. It contains a camera specially made for tracking IR signals.

Re: Indoor cat locator

Reply #4 –
Hmm, how about reversing the transmitter/detector placement? Maybe my cat should wear a photo transistor connected to a MCU interrupt ( good for deep sleep and power saving ) or comparator ( easier to handle signal strength calibration ) input and the forbidden places zones be lighten up with IR LEDs in a way that would minimize reflections so it can safely walk on the floor :)

@Sjaak: That's true.. but I think I will give the cat a chance before sending it to sleep on the balcony when it's -10'C outside ;P

Re: Indoor cat locator

Reply #5 –
I remember a project where they used a camera pointing down at a work area and software to detect motion.  Seems like some of the new cameras have that built in.

Now if I could just keep track of my wife.
"Too many projects, so little time"

Re: Indoor cat locator

Reply #6 –
Keep track of your wife and your cat: Max Home
... probably not what 'pppd' wants, since it has video cameras as part of the system components.

Re: Indoor cat locator

Reply #7 –
My girlfriend doesn't require tracking.. I am doing my best to focus on her when she's around so I do the tracking myself :P

The next thing I will document in the project log is an electrical energy meter optically interfacing the power company analog  device :) For now I just want to solve the cat problem.

Re: Indoor cat locator

Reply #8 –
I frequently lose my wife in crowds or department stores.  I frequently end up calling her cell phone and ask where are you.
"Too many projects, so little time"

Re: Indoor cat locator

Reply #9 –
[quote author="MichaelZ"]I frequently lose my wife in crowds or department stores.  I frequently end up calling her cell phone and ask where are you.[/quote]

are you suggesting a cat phone?

Re: Indoor cat locator

Reply #10 –
I started the project from forcing my cat to wear a collar. It doesn't like it and desperately tries to tear it off ( well, it's a she but I keep referring to it simply as a cat ) .. I hope that given some time it won't be able to live without its collar :) I will post some IR experiments results soon.

Re: Indoor cat locator

Reply #11 –
It's been a while since my last update.. but the project is definitely not dead. Actually I found quite a few people interested in this solution so this might go into limited production once proven successful :)

Idea which is being tested right now:

Cat wears a collar with an IR receiver ( TSOP1736 ) connected to INT0 of ATTiny2313 which stays in power-down mode. The receiver is powered up from another uC pin. In sleep/power-down mode the INT0 is configured for low-level wake-up as this is the only way to wake the CPU from power-down mode except for RESET. In this mode the current usage is below 400uA. This is still too much, but I don't think I could save much more with different IR receiver so I will need to live with that.

When it wakes up, it changes INT0 to be triggered by either edge. It then does all the data processing which is checking received ZONE ID. Current required for active mode at 4MHz / 8 is about 1100uA. After a successful zone identification it starts beeping and when cat leaves the forbidden area it goes back to sleep. Now this is the simple mode, but there of course gotta be more.. as I am a data collection freak :P

The collar will also be equipped with a small 2,4GHz transceiver (HopeRF RFM70). It will be powered down at all times ( just in case you are worrying about my cats health ) and will be used to notify supervising device about cat entering forbidden zone. The device will log each event in a database so I know if the cat is actually learning. Also depending on the time of day and my presence at home different penalty will be issued. For instance, I do not want beeping at night so instead the cat might get a puff of air or won't get a treat the next day.. we'll see.

The main problem is powering it up. Button cells do not provide enough operating time and I don't want to replace it every week or so. I was thinking about a small LiPo cell ( I have a few 240mAh, 180mAh, 300mAh which I use for DLG model planes ) protected by BOR reset so it goes into power-down mode when it's under safe voltage. Power usage in complete power down mode is about 15uA measured. I would need to put it in some kind of a fire-proof case as these batteries can be dangerous and I don't want my cat to burn in flames.

I will publish some clips and schematics next week :)

Re: Indoor cat locator

Reply #12 –
[quote author="pppd"]The device will log each event in a database so I know if the cat is actually learning. Also depending on the time of day and my presence at home different penalty will be issued. For instance, I do not want beeping at night so instead the cat might get a puff of air or won't get a treat the next day.. we'll see.[/quote]Ha!  I love cats, but I've never met one that was willing to be disciplined.  I would say that cats are incapable of learning, but they certainly learn things that they want to learn.  As far as disciplining goes, they seem incapable of learning what humans want them to do.

Good luck.  Sounds like a fun project in any event.

Re: Indoor cat locator

Reply #13 –
Quote
The device will log each event in a database so I know if the cat is actually learning.

lol, I also thought that was funny :) Thanks for the update. Is it the demodulator or uC that takes the power? You might be able to use another IR LED as a passive receiver.
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Re: Indoor cat locator

Reply #14 –
It's the IR demodulator that takes the power. I might try two stage triggering with a photo transistor which will activate the CPU and then the CPU will power up the IR demodulator. We'll see if this brings any savings. The good thing about demodulator is that it doesn't trigger when it gets lighten up by anything but a properly modulated IR signal. So the photo transistor/diode will only help if the power saved during IR demodulator being shut down is greater than required for running the CPU.

I will just do some testing.. I am not a big fan of theoretical calculations in such simple cases :)

Regarding cats not being able to learn.. I have heard/read that cats obey you only when you are around, so if you want them not to do something there must be something that's scaring them at all times not just when you are looking :) We'll see how it goes.. I will make the log public and accessible in real-time ;)