power on delay?

Discussion in 'General Electronics Chat' started by maniac1976, Jan 29, 2009.

  1. maniac1976

    Thread Starter New Member

    Jan 29, 2009
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    I'm building a custom set of tail lights for my car and want to make the tail lights sequence from the inside out i have some leds and can find the resistors but how do i make them sequence i was looking for some sort of power on delay but am having trouble finding anything. any suggestions?
     
  2. maniac1976

    Thread Starter New Member

    Jan 29, 2009
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    anybody? any suggestions?
     
  3. Wendy

    Moderator

    Mar 24, 2008
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    More information is needed. How many steps in the sequence, for example? You might give a rough draft as to what you're thinking about.

    It would be easy to overcomplicate this. I've seen automakers use a simple SCR arrangement to set 4 columns or so. When the turn signal breaks the current the SCRs turn off, reseting the sequence.

    You could also use 555 timers, or any other number of ways (a bar graph circuit with a ramp function, for another example).
     
  4. mik3

    Senior Member

    Feb 4, 2008
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    You can use a 555 as an astable oscillator which will drive a decade counter. Each output of the decade counter will drive a led or leds with a transistor and because the outputs of the counter will change (count up) in each clock pulse from the 555 the leds will turn on/off in a sequence. The speed the leds will turn on/off will depend on the frequency of the 555.
     
  5. maniac1976

    Thread Starter New Member

    Jan 29, 2009
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    ok i plan to have 8 columns of 4 leds i was thinking light them up in 2 column groups the only thing i'm not sure of is my flash rate once i know that i can set the timing when each group lights, for example if it flashes every second i would need each group to light .2 seconds behind one another leaving all groups on for the same time as the delay between groups. this is my first electronics project ever so please try to keep this simple any websites or wiring diagrams would be very helpful.
     
  6. Wendy

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    Mar 24, 2008
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    Are you planning on leaving the flasher in the circuit? Or are you going to feed the turn signal a steady DC level? Makes a difference overall. That SCR scheme was uses by autos depended on the turn signal clicker (whatever it's called), while any sequencers probably wouldn't (and would require tweaking to compensate).

    What I hear so far is something like this

    .Step 1: .. Step 2: ....Step 3: .. Step 4: .. Step5:
    ••ºººººº . ••••ºººº . ••••••ºº . •••••••• . ºººººººº
    ••ºººººº . ••••ºººº . ••••••ºº . •••••••• . ºººººººº
    ••ºººººº . ••••ºººº . ••••••ºº . •••••••• . ºººººººº
    ••ºººººº . ••••ºººº . ••••••ºº . •••••••• . ºººººººº

    Or is it the other way around?
     
  7. maniac1976

    Thread Starter New Member

    Jan 29, 2009
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    thats it and yes i would like to leave the flasher in the loop. it's only a 4 wire system so the brakes and turn signal are kinda on the same circut, the flasher just takes over one side and has the interupt. i want to use all original wiring up to the tail light assembly. if this works ok i might do a couple for my friends. if we stick with the flasher then we can get the timing set to the frequency of the flasher. i was hoping for some sort of 'power on delay' to install. the flasher would turn the whole thing off and start it all over, that way theres only 3 stages to worry about:

    1: power on would light the first 2 colomns and delay 1
    2: delay 1 lights 3 and 4 and powers delay 2
    3: delay 2 lights 5 and 6 and powers delay 3
    4: delay 3 lights 7 and 8 power stays on untill the flasher turns it off.

    this all depending on the existence of said delay
     
    Last edited: Jan 31, 2009
  8. maniac1976

    Thread Starter New Member

    Jan 29, 2009
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  9. Wendy

    Moderator

    Mar 24, 2008
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    OK, I'll draw something up. I highly recommend you breadboard this on something like a protoboard before tearing into your car, and I can't do a thing for you when it comes to your car's wiring. I know there is an SCR circuit out there that would be simplier, but since I don't have it at my fingertips I'll draw how I would do it, which is more complex. You might do a search to find it, I saw this circuit over 20 years ago in a electronics cookbook, it really was simple.

    I'll be back....
     
  10. maniac1976

    Thread Starter New Member

    Jan 29, 2009
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    thank you for your help i read a little on electronics every day to help myself learn what i'm doing not just doin it color by number style
     
  11. maniac1976

    Thread Starter New Member

    Jan 29, 2009
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    one more bit of info i just found there will be 2 wires bringing power in when both have power its for the brakes and the coloumn switch switches either side to the flasher so the flasher has to stay in the wiring so mabye I should make 2 boards one for each tail light that might simplify things
     
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