Connect with us

three led driver

Discussion in 'LEDs and Optoelectronics' started by jcurrie, Feb 22, 2011.

Scroll to continue with content
  1. jcurrie

    jcurrie

    128
    1
    Feb 22, 2011
    hi
    I'm a hobbiest that is trying to simmulate a mars light used on locomotives in the 50's and 60's , if it is possable to do this i need to light led one then light led two putting led one out then lighting led three putting two out then lighting two again putting three out then lighting one putting two out then going back to two again on a contunious cycle.
    thanks jim
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,419
    2,788
    Jan 21, 2010
    So you want it to go 1-2-3-2-1-2-3...

    One solution is to connect up a CD4017 so that output 1 connects to LED1, output 3 to LED3, and diodes from outputs 2 and 4 connect to LED2. Output 5 connects to reset.

    Then you'll need some sort of oscillator. to drive the clock input.

    The LEDs will light in the following order 1 2 3 2, and then the sequence will repeat.

    You could also do the same thing with a Pic (or indeed a PicAXE) but you'd have to learn to program them.

    I would probably lean toward using a picAXE just because it's relatively simple and everything would be much smaller.
     
  3. jcurrie

    jcurrie

    128
    1
    Feb 22, 2011
    thanks steve i thought about that but never thought about using blocking diodes on the outputs, have a circuit using a 4015 it should work on the 4017 , use output of the 4017 to drive transistors on it as they drive 5mm led. will the 4017 drive 3mm leds without them or should i use them as a safety?
    jim
     
  4. jcurrie

    jcurrie

    128
    1
    Feb 22, 2011
    Steve thanks again it works well have to tweek with the values to get the exact sweep, afraid i don't know a thing about Pic, any suggestions where to look to find info?
    jim
     
  5. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,419
    2,788
    Jan 21, 2010
    How do you want to adjust the timing? There may be some tricks that can be employed.

    If you want to start with pic programming, google for picaxe. It's a simple introduction and also relatively cheap.
     
  6. jcurrie

    jcurrie

    128
    1
    Feb 22, 2011
    Steve i just used a trim pot on a 555 oss to adjust the sweep .
    jim
     
  7. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,419
    2,788
    Jan 21, 2010
    OK, I thought that you may have wanted to have different ON times for each LED or something.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-