Connect with us

4017 Different LED count

Discussion in 'General Electronics Discussion' started by bigkim100, Jun 8, 2021.

Scroll to continue with content
  1. bigkim100

    bigkim100

    98
    0
    Apr 17, 2013
    Any way to get a 4017 (Driven by a 555) to count down rather than up. can this be switchable from counting up, to counting down LEDS?, or will I have to use something different than a 4017?
    Thanks in advance for any help
     
  2. PETERDECO

    PETERDECO

    174
    40
    Dec 19, 2019
    I believe the 4017 only counts up and returns to 0. A microcontroller, such as a PIC, can be programmed to do what you want and eliminate the need for a 555 in the process.
     
  3. bigkim100

    bigkim100

    98
    0
    Apr 17, 2013
    I dont know how to do programming for microcontrollers

    Is there a way to do it sans Microcontroller
     
  4. Martaine2005

    Martaine2005

    3,554
    966
    May 12, 2015
    Not sure I follow this.
    You can put the LEDs in any order you like. Also diode steering for more complex control.

    Martin
     
  5. bertus

    bertus Moderator

    2,019
    755
    Nov 8, 2019
  6. AnalogKid

    AnalogKid

    2,515
    718
    Jun 10, 2015
    For non-switchable, counting down only, just connect the LEDs differently.

    For switchable between up and down, you will need two chips (besides the 555). One is a 4-bit decimal or binary up/down counter. The other chip is either a 4-line to 16-line decoder, or a 3-line to 8-line decoder. Both are standard CMOS CD4000-series parts.

    ak
     
    Last edited: Jun 8, 2021
  7. Audioguru

    Audioguru

    3,382
    726
    Sep 24, 2016
    Like above, a "Road Runner" circuit uses diodes to steer the outputs of a CD4017 to make a row of LEDs light back and forth.
     
  8. AnalogKid

    AnalogKid

    2,515
    718
    Jun 10, 2015
    I think that is a "Knight Rider" circuit.

    ak
     
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

-