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Looking for a type of switch Answered

Hi People of Instructables!

I hope I am posting in the right place.
I am looking for a switch that when you walk pass a point it shuts off and when you walk the other way past that point goes back on.  

For example... I have a flash-light in my hand, when I walk through a doorway into a house the light turns off.  I go through the doorway the other way (to the outside) the light turns on.

It has to be able to do this through cloth as the flashlight could be in my pocket.
It can only work when you walk through the doorway but not when standing near the doorway

Does anything like this exist?  if yes what is it called?
I have been searching the 'net and not been successful as I don't have a clue what I am looking for.

Any help would be greatly appreciated.
Thanks for reading my post!



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9 years ago

The activate/deactivate switch may have to consist of two switches. These could be read by logic circuit or small microprocessor to determine the order in which they are activated, allowing the direction of travel to be determined. The actual switches could be two optical switches, where a light beam is broken as the person passes through. Another alternative would be pressure mat switches that close when the person steps on them.

As for controlling the flashlight, the base unit that reads the door switches could transmit a radio signal to either activate or deactivate. The flashlight would have to contain a receiver to receive the signal and turn the flashlight on or off according to the command it received.

I can't think of any device or system with this type of function offhand that would provide you an off the shelf solution. If you are serious, find an electronically inclined person to help with the details. If you have more detailed follow up questions once you get underway, try back here again, or in the "Answers" section.


Reply 9 years ago

Thank you for your response!

Although I was hoping that there would be something ready made at least you have steered me in the right direction.