Arduino Rotating Clock Divider

Hi all, I wanted to share with you my Arduino-based rotating clock divider. It features:

  • 8 buffered outputs

  • adjustable division from 1 to 199

  • 7-segment displays showing division

  • internal clock (20-600 bpm) with separate output

  • external clock input

  • rotate up/down and reset inputs

  • adjustable number of rotating outputs

More info, schematic, BOM and Arduino sketch are on Github: GitHub - TimMJN/Arduino-Clock-Divider: Clock divider module based on Arduino Nano, compatible with Eurorack and Kosmo modular synthesizers. Hope you enjoy! PS I have a few PCBs available, sent me a message if you’re interested.

All the best,



I really dig the blinking of the 7 segment as the indicator. Very well designed. :grinning:


Thanks!! It doesn’t come across too well on video, but it’s quite clear once you see it IRL

Saw this on Reddit, looks really cool! Love new Kosmo modules! :smiley:

Can you make a demo video showing some of the musical applications?



I have some more percussive voices coming in from Barton, I can make a video once I have those wired up. Though I must add, the concept of a rotating clock divider is not new, there’s quite some material online if you’re curious. Cheers!

Wanted to link you this one: Module requests - #437 by TimMJN

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Small update:

I’ve given the PCBs an update, mostly aesthetic. Also, flipped the rotate up/down buttons, seems to make sense this way.

I’ve also added a panel. It’ll just be a blank for now, as I have yet to determine the whole artstyle for my modules. For now, you’ll have to break out the sharpies, but at least there’s no more filing of rectangular holes.

I’ll verify the lay outs and send them off for manufacturing!


They’re in! The BST Thread (Buy, Sell, Trade) - #134 by TimMJN

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Hello! I’m new here, but I love your rotating clock divider module! I was wondering where you get the digital displays from. I’d like to take a crack at making it, but don’t know where to find those displays!

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Welcome to the forum! Thanks!

You could either buy them here: € 2,92 10%OFF | 188 DIGI Common Anode 0.25 inch Red 7 Segment display 0.25" no radix point LED Display 3 Bit Digital Tube Series Voltage Panel

Or you could send me a message, I still have a few pcb+panel+display sets available :smile:



Thanks so much! I actually would rather buy it from you with the PCB and panel but I’m wanting to adapt it to eurorack and I’m not sure I’d be able to do that. Thanks so much for your help!

No problem!

Ah okay, that won’t be straightforward from the PCBs. Probably, you’ll be off easier building it on stripboard/protoboard then. Unless, of course, you’ll be willing to build a 20cm tall rack. In that case you could simple swap out the jacks for 1/8" and be done with it. Cheers!

  1. Rotate the PCB 90° and build it as a 40 HP x 3U module. Of course the displays will then be sideways, unless you bodge up something for them.
  2. Build it on stripboard or protoboard or lay out a new PCB to squeeze it down to, I dunno, maybe 24 HP?
  3. Build a 20 cm case. It can be just a simple plywood box with wood rails. Switch the jacks to 3.5 mm, or don’t and use adapter plugs or jumbler panels. You can interconnect freely with Eurorack, and if you look around here you’ll probably find other Kosmo-only modules of interest to fill out the case.

If you’re really squeezed for space or need something portable, option 2 is your best bet. But option 3 is simpler and opens up future possibilities.

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If your Euro case is deep enough, you could put the PCB perpendicular to a panel, and use panel mount pots and jacks, wiring them to the PCB by hand.

Another option is to use the KiCad schematic and layout the board for Eurorack size, depending on how good you are at that sort of thing.

That’d have to be a case well over 8" deep, and there aren’t that many of them. Also a very great amount of wiring. (You’d have to wire the displays too.)

Yeah, that’s in there in option 2. A good way forward but requiring layout skills and effort. It’d be slightly easier if the KiCad sch file were available but I don’t see it in the repo.

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If your Euro case is deep enough, you could put the PCB perpendicular to a panel, and use panel mount pots and jacks, wiring them to the PCB by hand.

All good, viable options! Though I think panel-wiring this module would be one heck of a job, that’s 8*8=64 wires for the displays alone. Building a taller case would definitely be my preferred option, as you said, it opens up future options too.