Proximity Sensor recommendation?

[scarfie]

Can anyone recommend a proximity sensor to help me train sneaky dogs?

Scenario: dogs sneak into the laundry room and jump up on the counter to eat the cat food (and "snack" in the litter). We leave the door cracked 4 inches so the cats can get in, but the dogs can push by the obstruction with ease. Cat door is no good as one dog could fit through that... and the door would look ugly with that on there.

Solution: I would like to attach a tag to the dog's collar. I need a sensor that can detect the tag within approximately 3 feet. When the sensor detects the tag, I want to trigger a loud siren until it no longer senses the tag presence.

I am a total noob to this stuff. Can anyone recommend a solution (same or similar) that doesn't cost a fortune? I currently have no home automation or security implementations... willing to start. Any suggestions to point me in the right direction is greatly appreciated.

 

[LarrylLix]

Starve the cat so it fights with the dogs over the food. It doesn't take long for cats to become the "alpha dog".

Put out dog food for the cat. They usually love each others food for some reason.

 

[RAL]

Put out dog food for the cat. They usually love each others food for some reason.

 
 
Dog food does not contain key nutrients (taurine) that cats need in their diet.  Feeding dog food to a cat long term will kill the cat.

 

[dementeddigital]

Fatten up your smaller dog and install one of these:
 

 
In all seriousness, I would try RFID.  I think that the HF tags have a read distance of about three feet.  I would attack this one of two ways:
 
1. Install an RFID cat door, and put the tag on the cat's collar.
 
2. Put the RFID tags on the dogs' collars, and install a reader at about knee height.  The reader would trigger the alarm (either by sending a serial data string or activating a digital output).

 

[dementeddigital]

RFID cat doors:
https://www.sureflap.com/en-US (available on Amazon)
http://www.instructables.com/id/RFID-cat-door/  (DIY version)
 
RFID readers:
http://www.sainsmart.com/sainsmart-serial-uart-13-56mhz-rfid-reader-writer-module-kits-for-arduino.html
http://www.ebay.com/itm/like/231738627868

 

[cobra]

Or train the dogs...  Cats are a lot harder to train, but most dogs can be trained.  Seems like most people with dogs these days just give them run of the house and don't do any training.

 

[LarrylLix]

Cats require more l-taurine than dogs, but that doesn't mean that dog food has no taurine and dogs will suffer from pimentosis of the eye similar to what cats and humans would suffer from with a taurine deficient diet. Death is quite an exagerration.
 
As long as the food contains enough protein meats and/or fish, the taurine levels may be low, but usually sufficient. L-methionine shortages can cause the similar problems in animals. All the cereal garbage they dilute pet food with can be a problem lowering (essential to cats, dogs) amino acid levels.
 
Japanese researchers have done much experimentation with L-taurine in human nutrition to resolve ischemia of the heart. Dogs, cats, and humans do not manufacture this amino acid making it an essential amino acid in these animals.
 
Source: The Healing Nutrients Within....Carl C. Pfeiffer, Eric Braverman.
 
 
In the end the suggestion was only a bit of a joke based on how the animals always love the others food and not really a viable suggestion.