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The New Cat Door

For years we had used the standard cat flap for our cats to go in and out to their enclosure. A couple of years ago we had a couple of incidents where a cat caught his tail in the door. We have never figured out just how this happened, but probably just when the cat was almost through the door something startled him and he jumped back pushing the cat flap over his tail. When this happened the cat acted like the hounds of hell were after him. We started to look for an alternative to the flap design and found a motorized door from High Tech Pet Products that looked like it would solve our problem. The following pictures show how we adapted the door for our multiple cat household.

Cat Door(1)       Cat Door(2)       Cat Door(3)

The first two pictures above show the original cat flap. The next picture shows the enlarged opening for the new door.

Cat Door(4)       Cat Door(5)       Cat Door(6)

To provide a smoother appearance, a sheet of 1/8" MDF was used to cover the lower part of the door. The new cat door was installed. The cat door came with on collar mounted ultrasonic door opener. Since our cats never roam outside they do not wear collars. How to open the cat door without the collar opener? We considered several options including motion detectors but rejected them because they had too large a range of operation. We wanted the door to open only when a cat was directly in front of the door, the same as the collar opener. Our solution was to use a pressure mat that a cat had to step on before it worked. We found that these are hard to find in the U.S. and were quite expensive. However, a search on E-Bay found an inexpensive pressure mat in the UK. I bought two, one for £5 and the other for £1. The total investment, including shipping was about $25.

Cat Door(7)       Cat Door(8)       Cat Door(9)

The next problem was how to connect the pressure mat to operate the door. We did not want to connect directly to the cat door because that would void the warranty. It was decided to use the opener from the collar and to have the mat turn on the opener. The collar opener was powered by a 3 volt watch battery. The opener was modified to be powered by an external source. A Game Boy power adapter from Radio Shack was perfect and it cost less than $2. The center picture shows the test setup that proved the concept. Of course the messy wiring had a very low wife approval factor. The next picture shows the wiring after it was cleaned up. Note that the opener is mounted beneath the cat door. When activated it emits an ultrasonic signal that is detected by the door causing it to open. There is a pressure mat (under a small rug) on both sides of the door to open it when coming from inside or outside.

Cat Door(10)       Cat Door(11)       Cat Door(12)

Because we did not want to have a cat trapped in the enclosure if there was a power failure, the cat door is connected to a small UPS (battery backup). The completed cat door project is shown above. How have the cats adapted to the new door? It took a while. The door makes a noise when opening or closing that startled most of the cats. Some of our cats quickly learned how to operate the door but a couple of them took about 2 months to adapt. They all now use the door with no problems at all and there is no longer any chance of getting tails caught in the door.

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Photos on the border are by Helmi Flick

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