L.E.D touch ciruit help

Discussion in 'The Projects Forum' started by welshwarrior123, Mar 8, 2010.

  1. welshwarrior123

    Thread Starter New Member

    Mar 8, 2010
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    Hello guys, im new here and sadly know absolutley nothing about cicuits (good start hey :D)
    The reasson im here is I need some help fast, im currently taking my design technology A levels in which we are asked to design lighting for a purpose. My idea was a suitable background light that is LED and runs off a battery, but I require it to be touch activated.
    I planned on taking apart a normal touch lamp and put in the correct resistors for it to work inconjunction with the led's, but its an ac in ac out circuit so I cant use it, which I just found out today when we have 2 weeks left for the finished project to be handed in. Is there any place where i can by a pre made circuit for or parts to make a touch circuit for LED's. I would be very very grateful for any advice and you would probably save my A level grade aswell:) So I thank you in advance for your responses,
    Kind regards,
    Lewis
     
  2. Audioguru

    New Member

    Dec 20, 2007
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    Will your teacher allow you to simply buy a product or copy one instead of you designing the circuit by yourself???
    Are your studies just a joke???
    Is your teacher just a joke???
     
  3. welshwarrior123

    Thread Starter New Member

    Mar 8, 2010
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    I already have bought an existing touch lamp with the intent of using the circuit in my lamp. The problem is is that I have a specifcation that my entire project is based around in which i require a touch sensitive lamp, and with 2 weeks left theres no way I can change it. Now the circuit that i have got out of the lamp is an ac in and ac out touch sensitive circuit, i require it to be battery powered so it can run an led bulb. Now my teacher has had a look at the ciruit and sais that it cant be done. So all i want to know is there any way of aquiring circuit like that?

    I dont have the ciruit on me as its in my workshop but i dont know if it helps but these are the lamps that ive gutted for the circuits,

    http://www.argos.co.uk/static/Product/partNumber/4321046/Trail/searchtext%3ETOUCH+LAMP.htm
     
    Last edited: Mar 9, 2010
  4. Stills00

    Member

    Feb 16, 2010
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    So you want a battery powered touch lamp that powers a single LED? A few questions... What source voltage do you want to use? (9v, 3v, 1.5v) The switch you are trying to use is for AC not DC do you have to use that switch? Can you use something else? And how many LED's are you going to use and what color? If your not limited on the type of switch then you just need to built a simple LED curcuit with a switch.

    http://led.linear1.org/1led.wiz is a good site that has a basic LED Calculator...
     
  5. retched

    AAC Fanatic!

    Dec 5, 2009
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    Are you going to use a capacitance reading IC?
     
  6. Stills00

    Member

    Feb 16, 2010
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    Something like this?
     
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  7. welshwarrior123

    Thread Starter New Member

    Mar 8, 2010
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    I want it wired up to a 9v battery( or any type aslong as it will work), and the led's that i need are 4 white ones. I dont have to use the ciruit from the lamp and I understand that I could just build a normal led circuit but i require the switch for it to be touch activated, I realise i will need a capacator but I really no nothing about circuits.
     
  8. retched

    AAC Fanatic!

    Dec 5, 2009
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    You are going to need a little more than 9v for four white LEDs. The forward voltage for each is probably around 3.3v.
     
  9. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    A 555 works quite well as touch sw, tie pin 2 high with high resistance, around 3 megs, add touch plate or object to pin 2. Tie pin 6 low, or if self reset is desired connect 1M, pin 6&7 to high[9V] & 1uF pin 6 & ground for ~1 sec. Use two strings of two LEDs each with ~ 100 ohms in series with each.
     
  10. welshwarrior123

    Thread Starter New Member

    Mar 8, 2010
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    See this is something that would really help me if it can work, but as ive said I know absoultly nothing about circuits or components, so is there any way of simplifying it down for me (by that I mean in terms of explaining and wording)? Or is there any place i can buy a premade circuit like that, or any one that will comission one?
    Thank you very much for all the help and advice you guys are giving me here, you dont know how much your helping me.
    Kind regards,
    Lewis
     
    Last edited: Mar 9, 2010
  11. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    It works most of the time. Was used for model windmill [picture in my folder ] slightly modified for your application. Origional used C555, but for driving LEDs a regular 555 might be better. As shown produces 8 sec light pulse on touch.
    A simpler ckt uses a sensitive gate SCR[ 2N5060] to drive two strings of 20 mA LEDs. Tie gate to ground with 20M, touch plate to gate. 9V supply.
     
    Last edited: Mar 10, 2010
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