Dog Door Project, I need help please!!!

[Wiley_Oompa]

I have a dog door that is activated by a magnet that my dog wears on his collar. The problem is that whenever my wash machine or dryer are on, the door locks and unlocks constantly. My cat has figured this out and will sit and test the door till it opens, then he goes outside where he is not supposed to be.

I have decided that what I need to do is put some sort of IR transmitter/receiver setup on the door or something similar but I dont know where to start. I can build just about anything with a schematic, and should be able to adapt it to my dog door.

What I am looking for is some suggestions or information as to how I might go about making the transmitter/receiver.

I am just getting into circuit design in my Engineering classes and I figure I know enough to get through this with the proper information.

I greatly appreciate any help that is suggested.

Brandon

"If everything seems under control, you're just not going fast enough."

 

[Johnson777717]

Zonies Rock! :shock:

Sounds like you have a smart cat.

IR could work, but you'd need to add some sort of power supply to the collar for your dog. I'm not sure how often you are willing to charge or replace the battery in the collar. It may end up being pretty expensive in the long run.

Also, considering IR oscillations, if you put your ear next to a TV remote control and push a button, you might be able to actually hear the oscillations as a faint, very high pitched tone. I can hear my remote. My point here is that I'm not sure if the dogs ears will be sensitive to these tones or not, but I think that it is something to consider / investigate before building a full blown IR system.

Maybe we could look at the option of preventing the problem from occurring in the first place. I'm assuming that the washer and dryer motors create a large-enough magnetic field to throw off the sensor of the dog door? Is there any option of shielding this sensor from this magnetic field with the dog collar still operational? I imagine that this might be pretty difficult to do, but I suppose the opportunity is there.

Is there the option of placing the magnetic sensor on the outside of the dog door? Maybe this will help prevent the disruption without sacraficing the functionality of the door?

Perhaps the simplest fix would be to lock the dog door while the washer and dryer are running?

Just tossing out ideas...

 

[Wiley_Oompa]

Johnson,

Ya, the cat is pretty smart. Add that together with sheer determination and he gets out every time. I have played with the idea of shielding the sensor but its pretty small and mounted at the bottom of the dog door. The dog door also will lock and unlock when people/large objects are around it, that happens randomly though.

The instructions on the dog door state not to mount it next to a large electrical appliance but I really had no alternative. It does work, just gotta figure out how to make it so the cat cant get out.

I have a feeling that the sensor is either very sensitive or very crappy. If you have any suggestions as to how to possibly make it better that would be a consideration.

As far as the dog hearing the IR, I highly doubt it, he is stone deaf and couldnt hear a garbage truck roll by.

Thanx for your input so far, I hope to get this solved!!

Brandon

 

[Nigel Goodwin]

As far as the dog hearing the IR, I highly doubt it, he is stone deaf and couldnt hear a garbage truck roll by.

It's not a problem in any case, IR is light, not sound - so it's not possible to hear it (for anyone or anything).

If johnson777717 can hear something from his remote, it's either a very old ultrasonic one, or he can hear something inside whistling - not the IR.

 

[Phasor]

Well, if you're in for a little complexity, you could install an RFID system, with the RFID tag on the dog's collar. Somewhat similar to proximity cards used on security doors in many offices and units.

 

[KOEZE]

I don't know how the locking mechanism works but consider reversing the whole thing.

Put the collar on your cat and have the door lock in stead of opening.

When the washing machine is on the door is normally open but may lock sometimes.

As a mechanical option; Add a spring so that the dog with it's greater power can force itself trough the door open but the cat can't. My experience with cats is that when they find resistance they will not go through.

As to how smart a cat can be. We have a "dumb" cat door with a rotating cam that allows you to fully close the door, let the cats through in one direction and let the cats trough in all directions.
I have one cat that figured out how this works and can unlock the door. I have another cat that found that when the direction he wants to go is locked all he has to do is pull back the door and go through. Another cat (neighbours) found out that there is enough play in the hinges that the door can be lifted over the cam to allow access.
The only working option until now is a piece of plexiglass that can be attached to the door.

EJK

 

[McGuinn]

Himm... the complexities of life!
How about partialy shielding the pickup on the door, just enough to prevent the external sources from causing it to activate. Some alu-foil or tin should do it, but make sure all of the shielding is wired up together so that that any blocked current can flow throughout it.