Finished Pieces

Step sequencer

    I’ve recently redesigned this project and have made a bunch of changes to the circuit. Here is the most current schematic as of December 7 2011. Click the image below to enlarge.

    The schematic above is a substantial improvement over the other schematics below which I used in the past. I’m leaving them up for those out there who have used them and need them for reference. Other than that I strongly advise that you use the schematic above. It may be overly complex for your application but I tried to compartmentalize the schematic into its discreet parts so that it can be remixed as needed.

    This project is similar to the cam shaft sequencer minus all of the moving parts.
    I’m still working on getting all of the circuitry right.
    There’s a sample at the bottom of the page that I made using the sequencer to control a casio SK1,an analog bass drum synth and an analog noise synth.
    There’s also a casper built echo circuit in there.
    Here are some pictures of the first prototype.

    The sequencer is made up of four rows of 10 switches.
    There are four different sequences that can be programmed using the switches in that row.
    The left most column is an on/off switch for each row. The right column switches between “short” and “long” mode for each row. In “short” mode, the sequencer creates one 50% duty cycle pulse per step. In “long” mode the sequencer outputs a 100% duty cycle pulse per step. So it will string two or more pulses next to each other into one long pulse the image below should clarify.


    Here’s an awesome schematic of a programmable, rhythmic mixer sent in by SUBBS. Click the the image below to see a larger version.


    29 Responses to “Step sequencer”

    • 1

      Subbs said:
      September 15th, 2009 at 4:01pm #

      Here is my most recent build for a 4-channel, mixer sequencer. Meant to be played by 2 to 5 people.
      4 audio inputs are turned into patterns and beats by the “conductor.”

      Anyone have advice or corrections?
      If anybody wants the full-size image, feel free to ask.
      Much thanks to Pete for inspiration and aid.

    • 2

      casper said:
      September 15th, 2009 at 6:30pm #

      Thanks for the schematic Subbs. I added the picture to the project description above. Do you have any sound samples?

    • 3

      Sheik said:
      January 3rd, 2010 at 4:07pm #

      What sort of power supply do you use for this?
      I understand its 5 volts but, Amperage rating would be very useful.

    • 4

      casper said:
      February 18th, 2010 at 1:26am #

      @Sheik:The current draw for this circuit is pretty low. I’m sure the greatest pull comes from the relays. All told I’m pretty sure it under 100mA.

    • 5

      mikebike said:
      March 21st, 2010 at 9:27pm #

      can you explain the short/long step switch?

      its seems like you have a NAND gate or something but i dont understand how that makes it short

    • 6

      casper said:
      April 11th, 2010 at 1:07pm #

      @mikebike: the output of the 4017 is 100% duty cycle. so that means if you have step one and step two on, they will lead right into each other and you’ll have a step that is 2 cycles long. The output of the 555 timer is a 50% duty cycle. The AND gate combines the outs of the 4017 and the 555. The out of the AND is only high when both the 4017 and the 555 are high. SO it will go high when you set the step switch (from the 4017 out) on and for half a cycle because of the 555 50% duty. Make sense??? It’s kind of confusing but relatively simple as far as logic goes.

    • 7

      Mike C said:
      April 20th, 2010 at 7:02am #

      Does this schematic actually work? I would imagine there is some propagation delay through the decade counter that will prevent the clock signal from lining up with the pulse from the counter at the AND gates… any comments on this?

    • 8

      casper said:
      May 2nd, 2010 at 12:57am #

      Yup, it really works. The propagation delay is a few nanoseconds and the length and pulse width of the steps
      is long enough that even if they start a few nanoseconds off it doesn’t matter. In a musical context any delay is completely imperceivable. If the sequencer was running at extremely high frequency it might be an issue.

    • 9

      Gord The Rogue said:
      July 16th, 2010 at 8:35am #

      Hi! A quick question: where do you connect the sequencer’s output on the Casio SK1 circuit board?
      On the ribbon pins that recieve the keyboard events or on the classic bend points? Thanks a lot for this great site!


    • 10

      mike page said:
      August 31st, 2010 at 6:36am #

      Hi, ive been casually working on designs for a sequencer for quite a while (too long!). I want one to trigger where the piezos normally would on my electric drum. I was after more steps so ive tried (unsuccessfully) to cascade two 4017’s. A new thought occoured to me… maybe they could be driven by the two outputs of a darlington pair. This would’nt allow the 50% duty cycling thing (which might be a problem) but would be a nice tidy circuit!
      Any thoughts? also I dont know much about the 4016, is it working like a bank of relays in the above circuit? Cheers!! Mike P

    • 11

      Vanyamba said:
      September 7th, 2010 at 5:12pm #

      It needs the mute control input.
      MUTECTL___| |__________
      OUT ____||__||__||__||___________

      S1 OUT –> S2 MUTE IN
      S1 OUT –> INVERTOR –> S3 MUTE IN

    • 12

      Jeremy said:
      December 28th, 2010 at 7:29pm #

      Does it possible to connect each output to a transistor (like a BC547C) to make a 5v trigger signal?

    • 13

      JUNLAIS said:
      January 15th, 2011 at 6:17pm #

      Hello from Spain.
      Please, it´s possible to get this in stripboard, veroboard or pcb?
      I have few diy drum synth and I don´t know at all how to read schematics!
      Best regards.
      Thanks a lot.

    • 14

      casper said:
      January 17th, 2011 at 5:19pm #

      I am working on a tutorial for Make Magazine right now. It will include step by step directions on how to build one from scratch. I will post the instructions on my site once they are done.

    • 15

      GBOY said:
      March 16th, 2011 at 8:11pm #

      hi i want this on pcb 🙁

    • 16

      casper said:
      April 2nd, 2011 at 1:31pm #

      I’m working on a detailed article for volume 27 of make magazine right now. It explains in great detail how to build a sequencer.

    • 17

      Howard said:
      June 10th, 2011 at 11:25pm #

      casper, thanks for all of this information! 2 questions: will this sequencer allow two channels to be activated at the same time? also, can multiple sequencers use one 555 clock without making problems? can’t wait for MAKE 27!

    • 18

      allowishus said:
      June 14th, 2011 at 3:15pm #

      Hi! I just made this on pcb 🙂
      i made it with DIY Layout Creator, and uploaded the complete zip here

      nb: the external.jpg is from my first version, but the connections are the same

      @casper: feel free to host the files and/or use them for whatevs

      this beast is working, i gots the blinking proff right here

    • 19

      allowishus said:
      June 14th, 2011 at 3:25pm #

      btw. I can’t seem to make the circuit do the long 100% cycle. I’ve put the switch where illustrated in the layout, but when i switch it, it stops triggering all together. Any ideas?

      another thing. I’ve burnt one “channel” on one 4016 chip by connecting a homebrewed distortion pedal in series after the toy triggered by the sequencer. I don’t really get what the problem is, other than it doesn’t like (the 4016 gets really hot) sharing the same power supply as the distortion pedal. Any ideas on that one?

    • 20

      allowishus said:
      June 17th, 2011 at 7:12am #

      would you be able to connect relays to the RCA outs to prevent any shortage between the circuit and what is triggered?

    • 21

      allowishus said:
      July 6th, 2011 at 6:40pm #

      For those how may be interested, i’ve had no problems with the 4016 getting after i started running the sequencer at 6V instead of 9V

    • 22

      n.d said:
      December 22nd, 2011 at 12:09pm #

      @Casper. Can I make the sequencer with a cd4067?
      Do I have to change anything else?

    • 23

      casper said:
      February 16th, 2012 at 9:11pm #

      I’m inclined to say YES you could use a CD4067. I havent used that chip so I’m not overly familiar with its functionality but it seems to be a counter. I guess its big limitation is that it doesn’t have a reset feature but it is conveniently 16 steps. Hmmmm. Worth experimenting with.

    • 24

      plasticanimal said:
      March 28th, 2012 at 1:40pm #

      Just a thought here. Maybe a useless idea but, I was looking at a Toybiz Whack-a-Mole game and was thinking that it, or something like it, might make a good random sequence generator. The idea being to trigger different bends for my drum machines to get a “Illformed Glitch VST” style effect. There may be problems with the toy expecting user feedback to continue the patterns.
      Any feedback welcome 🙂

    • 25

      the_octopus said:
      May 27th, 2012 at 4:34pm #

      We built the old version of the step sequencer. It’s super cool to use it with cheap keyboards. I triggered the drumpads of a yamaha portasound.

    • 26

      the_octopus said:
      May 27th, 2012 at 4:35pm # the link

    • 27

      plasticanimal said:
      July 25th, 2012 at 12:53am #

      Ah, I see what you did there. It’s much like those Radioshock LED kits. I picked one up to use maybe for my bend sequencer. I got the Velleman MK152RS LED wheel. Didn’t realize the MK107 was the kit of choice for a sequencer. Anyone have tips on how to use the MK152RS for a bend sequencer?

    • 28

      ben said:
      March 6th, 2014 at 8:14pm #

      Hi casper, i’m actually thinking about making an 8 step sequencer for my toys, because playing three toys or more alone is impossible. But when i saw your schematic (the one with the 74HC08 IC), i had a reflexion : is it possible to add more channels (mmh 6 or 8 instead of four) following the same schem ? Did you ever try ?
      Sorry for bad english, i try to be at my best, lost in my french country…
      Thanks for answering.

    • 29

      TtF said:
      September 21st, 2014 at 4:24pm #

      Nice work with the sequencer, i’m going to make a 16 step version of it.
      I’m a newbie in electronics so I have got a question : what’s that thing that comes out of pin 3 of the TL071 and go in a 10k resistor “sensivity” ? what does the “sensivity” means ? also, what about the transistors just before the output jack ? How are they linked ?
      Thank you for answering, it’ll be helpful !


      Sorry for this bad English, I’m a French speaker

    Leave a Reply

    If you're not already logged in, there might be a question you need to answer before you post to prove you're human. It's there to help stop comment spam.