switch the light with your hand

Discussion in 'The Projects Forum' started by q12, Apr 10, 2009.

  1. q12

    Thread Starter New Member

    Apr 10, 2009
    3
    0
    "switch the light with your hand" this is my project i have started a long time ago and abandoned him because of lacking time and pissed off.
    Inspired from some SF movies (StarTrek and other) I was starting to build an switch who can turn on/off my light from my room.
    I was stopped at one point and cant resolve it ... and here I want the help from you. I was using an "field effect transistor" [FET]-blackPlasticCase and I cant remember the name of it... I know I was playing a lot with it to make it stable when i came with my hand in his area of "feeling" but he was then immediately screwup and fluctuate because it was instable.
    What I was trying to accomplish , is that on/off state, but he sensed when I came at him and then when I came out from him and this was the wrong part. I wanted only to "sense" the came at him part then stop sensing. then, when i came at him the next time I wanted to close the circuit.
    I was trying this with a led and see what was going on live.
    I , then , put in scheme an on/off circuit but the problem remain the same, because he sensed the way out from him movement and turn on/off the circuit like it was never there :)
    I hope I can make my self clear enough. If you can tell me about a new FET or a CI that can resolve the problem (or a quick&dirty circuit) .... because I want to restart my project again.
    thanks
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    You want a capacitance activated switch?
     
  3. q12

    Thread Starter New Member

    Apr 10, 2009
    3
    0
    if it works why not.
    a capacitance will do. after all i search for a cheap solution. the cheapest.
    :)
     
  4. q12

    Thread Starter New Member

    Apr 10, 2009
    3
    0
    any progress at that capacitance ?
    maybe some IC that can brake that long duration of sensing?
    I dont stay very well at coil capitol but i know it is possible to replace that FET with a coil. I think it runs at electomagneticFieldDisturbance principle.
    But im not exact sure.
    if you have done my testings and play like I was do, you will see that is a very big problem to resolve. the best way i think that is to choose a PIC (18f64-I still have them from a long time) but is a labor work. I search for simpler and compact results.
    thank you anyway. ;)
     
  5. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    We can offer suggestions, but I've got my own projects. Are you familiar with a thermin? It is a tank circuit, but the inductor is open. If you move any mass near it the inductance shifts, causing a frequency shift. When compared to a second oscillator at the same frequency (or close enough to generate a predictable beat) then you have something that could be the basis of a proximity type switch.

    You can also buy them off the shelf for industrial applications. Some liquid sensors are proximity sensors. Simple enough to use, 3 wires, power and the output.
     
  6. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    :D

    Theremin!

    Pretty good rendition of Video killed the Radio Star

    This one shows more how it is played, looks impossible:

    Classical
     
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