Sequential LED Bar w/555 & 4094

Discussion in 'The Projects Forum' started by ihod, Jul 18, 2011.

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  1. ihod

    Thread Starter New Member

    Feb 4, 2010
    Hello all.

    I am interested in creating a sequential led turn signal. I have scoured the web for schematics and I located one HERE. It looks legit to me so I built it and of course it doesn't work for me. I have checked and re-checked the connections and they are all correct.

    The LED at D1 which signals proper operation of the 555 timer is blinking like it should and adjusting the 100k pot makes it go faster and slower as expected. I cant get the 4094 to sequence through its outputs, it just turns them all on and they blink somewhat in sync with the 555. If I connect the switch wire, they go all go solid at once, not in sequence like they should.

    I guess my question is, is the 4094 actually suitable for this concept or would I be better off with a decade counter like the 4017.

    Maybe I am using the 4094 wrong...I made a separate PWM to serve as a "clock" for input to the 4094, put pins 1, 2, 15 and 16 to 12v (Strobe, Data, OE, Vcc) and pin 3 to pin 3 of the 555 (555 Clock Out to 4094 Clock In) and the 4094 just heats up and puts 12v to all the outputs.

    I also am curious about the operation of the FET Amp at Q1, I think it is being used as a switch of some sort when 12v is applied to the second input but I don't know enough about transistors to assume that's accurate.

    Please tell me, why do I fail? LoL
  2. wayneh


    Sep 9, 2010
    I think you misunderstood the schematic. As I read it, that LED configuration is a single cluster, all on or all off, to be controlled by a single output line. You need a cluster for each output to get the result you're after.

    Oops, this is automotive and will be closed.
  3. ihod

    Thread Starter New Member

    Feb 4, 2010
    Thanks for the reply!

    The cluster I get, I am planning on 10 LED's each and 9 clusters per side. What I am confused about is how to get the 4094 to sequence on its output pins because as of right now, it just turns them all on at the same time when I apply 12v to pin 2 (data) and blinks when I take that power away.

    Maybe I can try turning off power to strobe (pin 1) when the switch isn't being triggered.
  4. SgtWookie


    Jul 17, 2007
    Seriously, automotive modifications are on the Restricted Topics list in the Terms of Service.
    The relevant paragraph:
    As such, we don't discuss such projects on these Forums.
    There is a short list of forums that do support automotive topics in a thread in the Electronics Resources forum.
  5. ihod

    Thread Starter New Member

    Feb 4, 2010
    Even if the modification is for a show vehicle that isn't even registered?
  6. magnet18

    Senior Member

    Dec 22, 2010
    You'll have to contact the moderators about that, my guess is that it will still be closed, AAC is pretty strict about that, mainly because its "better safe than sorry" when it comes to legal issues.
  7. SgtWookie


    Jul 17, 2007
    The TOS does not make exceptions. If it did, it would say something like:
    • Automotive modifications, unless it's for a show car.

    Of course, then everyone would have a show car.

    So, no exceptions. As I pointed out, there's a partial list of other sites where you might take your inquiry.
  8. bertus


    Apr 5, 2008

    I am closing this thread as it violates AAC policy and/or safety issues.

    6. Restricted topics. The following topics are regularly raised however are considered “off-topic” at all times and will results in Your thread being closed without question:

    • Any kind of over-unity devices and systems
    • Automotive modifications
    • Devices designed to electrocute or shock another person
    • LEDs to mains
    • Phone jammers
    • Rail guns and high-energy projectile devices
    • Transformer-less power supplies
    This comes from our Tos:
    Terms of Service
    There will be enough sites where automotive questions can be discussed :
    Member selected automotive forums

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