I am sure you are kidding as many public restrooms already use such a system. As for the pet door, we have trained our Border Collie to ring a bell tethered to the doorknob when she needs/wants to go out. I am sure many dogs could be trained to activate the pet door in a like manner. I guess a timer could be utilized to lock it after a reasonable amount of time and a separate opener on the outside.
This just made me think of something that one of you maybe can answer. Do they make sensors for rooms so when you walk in the lights turn on and off when you leave? Light switches just seem so outdated...lol
I don't think that any "innocent child" would be attempting to enter a window that far above the ground, or, for that matter, why anyone innocent would be attempting to climb in a window. Anybody living in that house would already know about the connection and avoid the problem. OF course, an alternative to a direct line connection would be an electric fence charger, one of those used to keep cows in place. OF course, you make the assertion that any ac line shock is always fatal, which is incorrect. They may be potentially fatal, but the vast majority of 120 volt AC line shocks are not fatal. We only hear about the very few ones that are, we get no reports about shocks that are merely painful.
The original description was of a cat door placed quite a distance above the ground at a height that a child could not possibly reach. Most innocent children don't jump up that high. In fact, most innocent children are not six geet tall, as I recall.
As for live wires, I had to take some extreme steps a while back when the bulbs from my post light were being stolen repeatedly. I doubt very much that it was an innocent child taking out the glass and stealing the bulbs.
The successful doors that I have seen did not use a solenoid to open the door. Not only is the force to displacement curve the opposite of what is required, but also any solenoid able to do the job will draw way too much current. The commercial units that I saw used a small motor to raise the door, which does a far better job and consumes less power.
My families dog (Charlie) invented this decades ago. He trained the humans in the house to come and open the door at his command. He stood by the door and barked once. If we didn't respond in a timely manner he barked twice (you get the idea. When he wanted back in he did exactly the same thing.
May be people should just get smarter pets.
If WE were as smart as he was we would have taken out a patent.
As energy efficiency becomes more and more a concern for makers of electronics devices, researchers are coming up with new ways to harvest energy from sound vibration, footsteps, and even electromagnetic fields in the air.
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