Proximity sensor for dog door ?

I'm planning to make a PIC controlled automatic dog door for my Bernese Mountain Dog puppy, I've looked at the commercially available doors and they have many reviews indicating that they don't last long and cost $$$.

The only problem I have is how to detect when only my dog needs to go in or out. I know I need to have some type of transponder or transmitter on his collar, either RF or IR.

My car has the keyless entry/start system and I know of retrofit kits for this and I could hang the "key" off his collar and feed the input to the PIC.

I'd appreciate if anyone could please pass along any ideas or suggestions on how to do this.

Thanks for any help !

I have one of those " autoslide " door openers , it came with a pet sensor . I don't have a pet and was curious about how it worked so I pulled the pet sensor to bits. the dog/cat end is a strong magnet that's hung from the collar "key ring style" . the sensor is a hall effect sensor set at the appropriate height on the door jamb for you pet .

Why not something like THIS? You can get dogtag-type RFID tags for a few dollars.

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Originally Posted by andywpg

Why not something like THIS? You can get dogtag-type RFID tags for a few dollars.

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I have one of the SparkFun RFID's and the range might be a bit short say about an inch.


Norm

Thanks for the replies ! I have made hall effect sensors for my CNC router, I think I used SS441's and they work great and reliable. However, I don't know what kind of range I can get from them. I used weak magnets for the router, I'll try some strong magnets and see how they do.

Unless the SparkFun RFID units can be modded to increase range, I don't think that will work, I think I need around 2 feet of range or at least 1 foot. I found THIS but the range is only around 4".

Thanks again, please let me know of any other ideas/suggestions.

Well, how about... teach your beautiful dog how to press some kind of button to enter/exit !?

don

For going out you could use a PIR sensor as you assume once in it's your dog that wants to go out. You could use one for coming in also but you'd not have any verification it's your dog. It would be the same result as a magnet though. An advantage to this approach is cost. PIRs are cheap, don't use much power and most have an adjustable range feature.

If you didn't mind something more interactive you could weigh your dog and input that to your PIC or have a learn mode. Either might be painful as the dog might not step on entire pad, might drink alot of water or get caught in the rain. Any would throw off the saved weight.

I still wonder if RFID might be your best least complicated for the dog solution. Though usually as soon as I say it someone else says I'm wrong. Good Luck.

if it helps ,the autoslide used a Honeywell hmc1001 sensor

fyi
I just powered up the pet sensor and put the cro on it. it reliably detects the magnet at 450mm (18") , it also seems to be more sensitive to the magnet being in motion which is probably a good thing for a pet door .
hmmm..... must be useful for something

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Originally Posted by amgen

Well, how about... teach your beautiful dog how to press some kind of button to enter/exit !?

don

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I actually never thought of that ! Good idea but, I'm trying to train him for several basic things and he's learning great. I really want to do this PIC based though.

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Originally Posted by richard

fyi
I just powered up the pet sensor and put the cro on it. it reliably detects the magnet at 450mm (18") , it also seems to be more sensitive to the magnet being in motion which is probably a good thing for a pet door .
hmmm..... must be useful for something

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Thanks for testing it Richard ! ~18" will be fine. I'll test with the SS441's and see what kind of range I can get, I'll order some Honeywell hmc1001's if needed.

Thanks again !

Quote:

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Originally Posted by richard

fyi
I just powered up the pet sensor and put the cro on it. it reliably detects the magnet at 450mm (18") , it also seems to be more sensitive to the magnet being in motion which is probably a good thing for a pet door .
hmmm..... must be useful for something

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Richard

Could you provide a description of the magnet including size?

Norm

I can't open it up but my best guess is a 6-8mm rare earth magnet

I did a bit more testing , a ugn3503 could detect the magnet at 5mm , the compass in my mobile phone could be moved from about 150mm

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Originally Posted by richard

I can't open it up but my best guess is a 6-8mm rare earth magnet

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Richard

For those of us who are metric challenged is the rule seen in the photo in centimeters?
Is the magnet enclosed in a plastic shell?

Norm

correct in both counts ,ruler is in cm and housing is plastic

Hi,
Maybe this would work using one axis. I bought one but have not tried it yet.

http://www.ebay.com/itm/HMC5883L-Tri...item4d1e7ea3b8

Add:
I just found this pdf. There is a reference to an example in basic
http://www.parallax.com/sites/defaul...ation-v1.0.pdf

http://www.parallax.com/search?searc...ompass&=Search

I did testing of the Honeywell SS441 on the bench and max range is only about 1 inch. And that's with very strong neo magnets so I'll order some hmc1001's.

And I'm still looking for RFID units with decent range.

Quote:

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Originally Posted by Sam

I did testing of the Honeywell SS441 on the bench and max range is only about 1 inch. And that's with very strong neo magnets so I'll order some hmc1001's.

And I'm still looking for RFID units with decent range.

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Sam

SkyeTek is the closest RFID I have found so far but I am still looking for a good 2' range unit a the lower price point.

Norm

If you want an RFID solution this thingy, http://www.farnell.com/datasheets/682634.pdf says it has less than 24 inch range and costs around $8 American, not including shipping. This is one of the readers from TI, http://www.farnell.com/datasheets/1719520.pdf, but I dont' think it has an antenna and that would be another expense. I wonder though if you couldn't have more than one antennae but use that same reader module. That way you could not only open the door but dispense a treat, daily food and/or water depending on where the dog, or the owner, brought a key fob.

The only reason I picked TI is that their stuff came up first during a search and I tried to get matching technologies. There were several different manufacturers but our company uses Newark for most of our common electronic parts supply so I'm basing cost off their prices. I'm not an engineer or a usually fully successful experimenter. I just had some time free for searching.

I'm assuming through all this you want to make sure your doggy door opens for your dog and not someone or something holding a magnet. Best of luck and please keep the forum updated.