Drag Race Tree Circuit Help

Discussion in 'The Projects Forum' started by robrob, Jan 27, 2012.

  1. robrob

    Thread Starter New Member

    Jan 26, 2012
    Does anybody have an existing circuit for a drag race tree or can make on up? I've seen them with microcontrollers and relays here and there. I want to use logic ic's, led's and something like a 6v power source and no clock. I don't need any fault start or pre-stage lights, just the count down to green. Probably like 3-4 yellow then a green. I've made chasers, counters and basic stuff before but need some help. I also have Multisim if anyone has something in that.
  2. w2aew

    Active Member

    Jan 3, 2012
    Lots of ways to do this. An analog-type approach would be to make an integrator to give you a linear ramp which is applied to the inputs of 3 or 4 comparators with gradually increasing threshold voltages. The outputs of each comparator will drive an LED. Of course, this leaves each LED "on" as the tree counts down.

    Simple digital approach is a simple oscillator driving a counter into a decoder - then the outputs of the decoder drive LEDs.
  3. praondevou

    AAC Fanatic!

    Jul 9, 2011
    For the people those not so familiar with drag racing can you please post the exact timing and sequence requirements of the circuit you want?

    Like, LED 1 on for so long, then LED 2 on... then LED 1 off etc. The more information the better.

    6V, logic ICs and LEDs. Only one LED per stage? If not, how many? High power LEDs? Normal LEDs?

  4. thatoneguy


    Feb 19, 2009
    There also needs to be a sensor for feedback to show the red lights if the car moved too soon.