6 led chaser circuit

Discussion in 'Digital Circuit Design' started by fusionwerks, Oct 27, 2017.

  1. fusionwerks

    Thread Starter New Member

    Oct 11, 2017
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    I would like to build a 6 LED chaser circuit that just goes one direction, 1-6 and back to 1 Using 4017 and 555 ic's. I would like it to be adjustable through a pot if possible to control the speed rather than guessing at values and hoping its right. YES, i know it sounds like a simple google question, but i cant figure something out. All of the 6 led circuits i have seen online are back and forth (scanning/knight rider) circuits with diodes making them activate the LED's on the remaining outputs of the 4017. I have tried to draw this circuit in circuit sims, and only using 6 outputs on the 4017, but how do i get it to skip the unused outputs so there is no delay before it starts back over to 1?
    Im sure this is simple, but i just cant find the answer
     
  2. dl324

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    Mar 30, 2015
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    Just reset the counter.

    But, you can't make a CD4017 count down...
     
  3. bertus

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  4. fusionwerks

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    Oct 11, 2017
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  5. bertus

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  6. fusionwerks

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  7. bertus

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    Hello,

    Then tie the ouput of the 7th led to reset.

    Bertus
     
  8. fusionwerks

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    Oct 11, 2017
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    sorry to be so hard headed, but do you mean the 7th output of the 4017 to reset? I wont have a 7th LED
     
  9. dl324

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    You're using the 7th output to reset the counter to 0. So it will light the first LED and not a 7th that you won't have.
     
  10. bertus

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    Hello,

    As soon as the 7th output goes active, it will reset the 4017 and the 4017 will start at the first again.

    Bertus
     
  11. fusionwerks

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    Oct 11, 2017
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    Is there any kind of resistor or something that goes in line with that?
     
  12. dl324

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    No.
     
  13. bertus

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  14. fusionwerks

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    Oct 11, 2017
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    I get it now. Thank you, the simulator that i'm using doesn't seem to show a reset pin on the 4017, so i couldn't experiment with it.
     
  15. dl324

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    Then it's a good thing that the circuit is so simple that you don't need a simulator...
     
  16. Reloadron

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    Jan 15, 2015
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    What you want is commonly called a count to n and recycle where n is whatever you want it to be. The link is just an example using the 4017. :)

    Ron.
     
  17. Audioguru

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    Dec 20, 2007
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    I have a chaser using a 555 clocking a CD4017 and its output transistors are emitter-followers (the LED with its current limiting resistor is connected to the emitter of the NPN transistor and 0V). There is a resistor from the output of the CD4017 to the base of the transistor and the base has a capacitor to ground then the LEDs brighten and fade and the chase has a bright LED followed by fading previously bright LEDs.
    I made another brightening and fading chaser that goes back and forth (knight rider).

    I have another "chaser" made with 50 LEDs of 5 colors (I retrieved them from Christmas tree lights thrown away). Each color has 10 LEDs mounted in diagonal rows and the colors and their diagonal rows light one after the other then all 50 LEDs light for a count and the last count has a pause with no lighted LEDs.
     
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