??????strange 556 timer question?????

Discussion in 'General Electronics Chat' started by itel933, Oct 28, 2010.

  1. itel933

    Thread Starter Member

    Aug 26, 2010
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    I used a 556 timer to intergrate 2 circuits, a tone genrator and a countdown timer. When the unit is on there is a green LED indicator light. At the expiration of the countdown a vibrator turns on letting you know that "time is up" there is also a red LED that lets you know as well.

    Problem # 1 The countdown timer is set for 8 mins, but when I switch on the unit and I start to create tones the countdown goes from 8 mins to about 3 mins. why is that?

    Problem # 2 After the expiration of time. When I switch off the unit, then try to turn it back on, the vibrator turns on immediately along with the LED. I have to cycle the unit on and off several times to get the vibrator to stop and have the unit work properly....What is wrong with that?
     
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    Last edited: Oct 28, 2010
  2. t06afre

    AAC Fanatic!

    May 11, 2009
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    Hard to say. Then posting in this forum. Always post complementarity information like schematics and code in the first post. Your benefit will be more, quicker, and better answers.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
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  4. itel933

    Thread Starter Member

    Aug 26, 2010
    38
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    Here is the plans
     
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