led chaser taillights

Discussion in 'The Projects Forum' started by sanctfy, Jan 31, 2010.

  1. sanctfy

    Thread Starter New Member

    Jan 31, 2010
    7
    0
    1. this is my first real project so i dont have a lot of knowledge on some of this stuff but im doing led taillights i got the brakes all done but im working on a chaser sequence for the turn signal. the power in is a 12v power that goes high to low(blinks). i have an an4017 ic and have it hooked to straight power for testing purposes. i cant figure out how to regulate the chaser speed. all the schematics ive seen use a 555 timer or a nand gate. can i use the high low power from the power source and throw a capacitor and resistor in somewhere to slow the chase speed to something im looking for or do i have to get a 555 or nand gate?

    so my question is how do i slow the blink without a 555 timer? do i have to use a nand gate? i already have oscillating power.

    this is the turn signal that i want.
    <object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/p2GrPYo1Cn...xcfcfcf&hl=en_US&feature=player_embedded&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowScriptAccess" value="always"></param><embed src="http://www.youtube.com/v/p2GrPYo1Cn...xcfcfcf&hl=en_US&feature=player_embedded&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" allowScriptAccess="always" width="425" height="344"></embed></object>

    thank you. i ve been searching for days and just cant find the info i m looking for.
     
    Last edited: Feb 1, 2010
  2. sanctfy

    Thread Starter New Member

    Jan 31, 2010
    7
    0
    someone know something about this?
     
  3. whatsthatsmell

    Active Member

    Oct 9, 2009
    102
    4
    Getting the lights to flash the way you want is easy. Designing the system so that it is D.O.T. approved is the problem. I think that is why everyone is hesitant to jump in. There could be liability issues. :(
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Canada passed a law making it illegal to modify brake signals/turn lights because many accidents were being caused by youngsters trying to make their own.

    It's definitely become a safety issue.

    You can't just buy some cheap LEDs from an auction site and expect to make a reliable light that complies with all of the regulations.
     
  5. sanctfy

    Thread Starter New Member

    Jan 31, 2010
    7
    0
    i just need to know how to make the chaser slower. we can say its for a different project. the tails are already done minus the chase.

    ill have to look into this dot thing i suppose. they seem brighter than stocks and serve the same purposes. is there a web site for checking dot regs? what kind of problems were they having?
     
  6. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    The clock oscillator of a chaser determines its speed. A single resistor or capacitor in its oscillator circuit.

    Kids are using cheap dim LEDs on their cars that have a viewing angle that is too narrow to be seen slightly off axis. The LED tail-lights are sold in many stores here in Canada because the law bans using them, not selling them.
     
  7. sanctfy

    Thread Starter New Member

    Jan 31, 2010
    7
    0
    i can get it to speed up but how do i get it to slow? i attach a longer wire and the thing will speed up.

    also ive ran into another issue. testing it on a 12v plug in adapter it works pretty well. without hooking up the clock pin at all it chases. a bit fast but thats the prior issue. but once i hook it up to the automobile dc power it acts differently and just the one pin lights up. i hook it up to the pulsing power and it will blink three rows then skip 2 rows. maybe because the clock wire needs to shut completely off and the blinker circuit only goes dim? will the high low blinking power wire hooked up to the clock wire be efficient as a oscillator? it seems to be very sensitive to static.
     
  8. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    You forgot to attach your schematic so we can't see how the CD4017 chases without a clock oscillator.

    Maybe you are clocking it with the blinking power. Then the clock pin goes high but nothing makes it low.

    The clock oscillator must be fairly fast then the blinker can slowly activate the enable pin or reset pin of the CD4017.
    It must be reset with a resistor and capacitor when power is applied.

    It needs a supply bypass capacitor close to its power pins.
     
  9. sanctfy

    Thread Starter New Member

    Jan 31, 2010
    7
    0
    [​IMG]
    4017 pin connection diagram


    [​IMG]
     
  10. sanctfy

    Thread Starter New Member

    Jan 31, 2010
    7
    0
    thats what i have thus far. the blinker can blink about 5 times a second if i dont put a load resistor in the line cause it trips the rapid flash. will that be fast enough? basically it looks like when it blionks high it lights up 3 rows and when the blink is low it doesnt reset it just doesnt have power to light up the next two rows then goes high to light up the next three.

    so i should
    1. put capacitor in power line.(assuming a 1uf?)

    2. (option 1) put a capacitor or resistor in the line from output 6(first output pin not used) to reset. or i hook it to the blinker?

    3. (option 2) if blinker is fast enough hook it to clock and put a resistor or capacitor. if not fast enough ill need a nand?

    what is the purpose of the enable pin?

    thank you very much for your help
     
  11. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Yes, from the positive supply voltage to ground.

    You are using the reset pin but it also must be reset when power is applied. Then the first output will be high so do not connect an LED to the first output.
    You must use a gate for the reset to have two functions. Two diodes and a resistor to ground form a gate. A reset will occur when power is applied when the input to the gate has a capacitor to the positive supply.

    The blinker pulses high. It never goes low so add a resistor to ground to make it go low. You don't need a capacitor since you use the blinker as an oscillator. Then the clock pin will go high and low the way it is designed.

    But the blinker is mechanical (a relay?) and will quickly wear out.

    The Enable pin is normally low. When it is high then the counting stops.
     
Loading...