Considering project: vibrating motor activated by pressure sensor

Discussion in 'The Projects Forum' started by Sutitan, Nov 12, 2009.

  1. Sutitan

    Thread Starter New Member

    Nov 12, 2009
    Idea: having a mechanoelectrical pressure sensor, that when fully pressed, would activate a tiny vibrating motor for a fraction of a second.

    Inspiration: My grandfather recently lost all the feeling on the bottom of his feet. this makes walking kind of difficult since its hard for him to tell when he has actually stepped. he is in generally good health (used to run five miles a week prior to), and still walks. I discussed possibly trying to make something to help him with walking.

    Application: I planned on installing the sensor(s) in the sole of his shoe. when he steps, pressure would be applied, and a little vibration would give him some tactile feedback.

    Challanges: I have no clue about how to really approach this problem. all ive really managed to do is possibly track down parts that could be used. id also need a way to make sure that it just gives a fraction of a second of vibration, as apposed to it staying on while he is stepping. I also need a way to make sure that the vibration only occurs once per footstep. so possibly like a switch the closes when the pressure is fully applied, but as soon as the pressure is gone, the switch opens. just thinking outloud...

    Parts ive looked:

    Piezoelectric Film Sensors

    Vibrating motors

    If anyone could possibly provide any help (maybe even a reality check for someone inexperience with electronics) it would be pretty helpful.

    thanks ahead of time
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    You could use the conductive foam that CPUs and IC's come in, it shows less resistance when it is squeezed.

    Run a battery through that and a comparator (or just a transistor) to turn on the motor when the resistance is low enough. The foam won't carry enough current to run the motor itself.

    Not sure about how to limit the length of the pulse to the motor without getting a bit more complex.
  3. Duane P Wetick

    Active Member

    Apr 23, 2009
    How about those little vibrators they use when you are waiting for a table in a restaurant? Ask the manager if they have some that quit working...maybe he will give you one and then you can open it up and see whats inside? Let us know, ok?

    Success will be yours, DPW
  4. Sutitan

    Thread Starter New Member

    Nov 12, 2009
    Thats actually pretty interesting. could work. id just be worried about the degradation on the foam over time. depending where i place the sensor, im afraid that possible moisture or the pressure would mess up the foam, but I guess that applies to the whole project

    that sounds like it would work pretty well with the sensor if understand transistors properly. i could basically use the current from the sensor to switch a bigger current coming from a battery.

    Im all ears :)

    ill try ask every time i go out to eat now. who knows, there might be some just collecting dust in a restaurant. as far as how they function, I think they are microprocessor controller. they just have a reciever, and when a signal is received, it goes nuts.
  5. Bernard

    AAC Fanatic!

    Aug 7, 2008
    Just tried a small strip of conductive foam between two copprr coins, with moderate pressure pulses, resistance between 200k & 30k. Lonjivity ??
  6. yfx4

    New Member

    Sep 30, 2009
    The little vibrating motors I have run on 1.5 volts and are from pagers. I bought them for $0.99 at the electronics store. Some folks use them in little robots. Perhaps you could attach it to a velcro strap and wrap it around his leg with the wires running up from the shoes.

    Good luck and my best to you and your grandfather.