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analog method to blink led when infrared beam is broken

Discussion in 'LEDs and Optoelectronics' started by Beverageexpert, Aug 23, 2011.

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  1. Beverageexpert

    Beverageexpert

    1
    0
    Aug 23, 2011
    Hello I am a noob with analog circuits as I started learning with microcontrollers. I know this would be easy with a microcontroller but would like to have it more simple.

    I have an infrared led and infrared phototransistor that I would mounting in a jar. Anytime somebody puts something in the jar I would like it to blink the led. I thought a pnp transistor would do the trick but it is not working. When I shine the infrared led on the phototransistor the led lights up. I want this to be reversed. Any suggestions?

    Thanks
     
  2. duke37

    duke37

    5,334
    751
    Jan 9, 2011
    Draw your circuit, scan or photo it and post it here. Almost certainly this can be done with a transistor and a couple of resistors.
     
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