traffic light help using 555 timers

Discussion in 'The Projects Forum' started by miketest, Feb 15, 2014.

  1. miketest

    Thread Starter New Member

    Nov 9, 2012
    Ok, so my project is to make 2 traffic lights with different timings on their own using 3 555 timers... the idea is to use the first 555 timers output as the source for the other two timers.

    the problem is that when I calculate for the resistor values, the timing for the circuit gets messed up. I looked into it and saw that the problem comes from the initial charging towards 1/3Vs for the capacitors... i could calculate it in, however for succeeding cycles, this charging cycle is no longer done..

    so my question is that how would you design a circuit so that the capacitors never go below 1/3 Vs..

    tl;dr the initial charging time of the cap from 0 to 1/3 Vs is messing with my timing because its not really present in net cycles, is there anyway to work around that problem or can i even have a vary the frequency and duty cycle automatically
    Last edited: Feb 15, 2014
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010