Question regarding Inductive Proximity Switches

On reading this, the first thing which comes in my mind is that Inductive Proximity Switch is more sensitive towards ferromagnetic material. This means that if you keep your sensitivity to the lowest, the proximity sensor will probably only detect the ferromagnetic metals around it. But that doesn't solve this case fully. To detect a magnet (Magnetized material), you need to detect the magnetic field of that material, which, sometimes will be misguiding when you want to find something randomly. If you have to detect a magnet which you are placing, you can solve it by placing a really strong (alloy) magnet, and use a low sensitivity detection mechanism to detect a magnetic field that strong, and thus solving the purpose.
By the way, if you can give an idea of what you REALLY want to know, where do you want to apply, I hope we can help.

Hi AJ,

Thanks so much for your response. It's actually something I'm trying to work out for my dog 😀. He sleeps in a crate but he hates having the gate closed and whines when it is. I'd like to leave the door open but still train him not to go out, by triggering a vibration on his collar when ever he tries to leave the crate. The issue is that since the crate is only half a meter long, it needs to be only sensitive enough that the mechanism will trigger when the vibrating device and sensor pass directly beneath the door of the crate and not when he's sleeping nearby. This would be similar to an alarm sensor on a window. But since the crate is made of metal, I don't want to pick up the rest of the metal, only the specific one on his collar. I know that they have shock collars which transmit to an invisible perimiter fence for outdoor yards. But I don't know if the sensitivity could be calibrated to only sense a field a few centimeters away. I know the whole thing is kind of silly but I'm doing this more as a project to see If I can make it work. Any insight you have would be greatly appreciated. Thanks again!

Josh

The simplest idea would be to place a removable rod vertically in the middle of the door covering the whole length, or one horizontally covering the width. The rod must not come out if pushed from inside.
Or, replace the rod with a laser beam, which if cut, would trigger the vibrator in the collar. The communication between the laser beam and the collar can be using a radio transceiver.
What do you think?
I just saw your reply. I am at work, so I couldnot think much. Will think about a better solution if this one is not an acceptable solution. 😀

Make the door out of a transparent hinged plastic. A lever operated limit switch can easily sense the opening of this and trigger the collar vibrator. Since the dog can see out he may stay put also. Only problem is that if the dog likes the vibrator he may intentionally open the door frequently. Even simpler is to attach a vibrator to a floor board and directly operate it with the limit switch. You won't need a wireless link to the collar then. You will have to add a toggle switch in series to activate the vibrator as needed.