traffic light circuit

Discussion in 'The Projects Forum' started by hami007, Jun 6, 2009.

  1. hami007

    Thread Starter Member

    Oct 26, 2008
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    i have build a traffic light circuit (three LEDs) by using 555 timer and 4017 decade counter
    but i also wanna show count down on 7 segment display (such that it will count down till green led is on then reset) how can i make it help me out thx
     
  2. Wendy

    Moderator

    Mar 24, 2008
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  3. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Here is a brief outline for yellow light count-down. The 555 is speeded up to supply count-down clock & counted down to supply lights.Fast clock at 1pps, is gated with yellow output to drive a 74C192, BCD UP/ DN counter which is pre-loaded to "5" or other desired count; BCD output to 4511, BCD to 7 seg. disp. May require a little more logic control.
     
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