Tuesday, 15 November 2016

Korg Mini-Pops DIY Drum Machine

Korg Mini-Pops DIY Drum Machine 

This is a really cool build;  It a recreation of the Korg Mini-Pops drum machine, an instrument which has been on a ton of records the most famous of which might be Jean Michelle Jarre’s ‘Oxegen’ album, hence this clone being called the ’O2’.  

The brilliant Jan Ostman built this using only an Arduino nano and a few barebone parts.  Jan is giving away the full details on his website and is only asking for a $3 donation in return.  Bargain!

I started by building my first version using a cheap Maplin plastic enclosure, but I thought it was worth spending a little more time on it so I got the table saw out. 

Because the table saw has a maximum cutting width of 7cm, I based the case around this limitation.

The switches mute the individual drum hits. The pots select the pattern and its tempo.

***UPDATE Arduino Drum Machine****
Simplified Schematic

Ok, so this 'simplified' schematic might not actually make things any simpler!  But some people have asked for it, so maybe it'll help clear somethings up a little bit - especially how to wire up the audio output and pots/switches.  This was drawn from memory so I hope it's correct - give me a shout if not and I'll update (the pots might work in reverse, but they'll still work).  I'd also urge you to look at the schematic on Jan Ostman's website for more help;




  1. Replies
    1. Thanks Jan! I've also built your string synth but haven't had chance to write it up yet, here's a video for the time being;


      Thanks for sharing all your hard work - I've learnt so much!

  2. Hi, really nice build! I am planning on making this my next project and I have some questions. I see a MIDI jack in one of the pictures, is that somehow hooked up to a CD4067 to drive a sequencer? How did you implement that? I have used an Arduino Uno for several projects, but I've only read the datasheet for the CD4067 and have no experience with using one.

    1. MIDI output was added into the code so now the drum machine can set the tempo of other instruments - no CD4067 was needed. Notes and volts have a great series about Arduino and MIDI;
      They originally built an Arduino synth, then came back to the project later and added the MIDI. Maybe you might be able to figure out how to add the code yourself after reading (it also has a MIDI out schematic);
      If not, maybe this guy might share the code if you ask nicely ;-)

    2. Ah, so it's really MIDI out! Thank you for the info, hopefully I can get it figured out from here.

  3. NIce project, really very cool :)
    I try to make it and didn't work :( I read we don't need the MUX as the original scheme. I try many combinations, tested the speaker, checked the cables.... nothing :(
    I'll keep trying :)
    Thank you for this project :)

    1. I got it :) It works so well, I post this cause some people could have the same problem. I used a wrong capacitor at the end (yes, stupid). I mess up the values in the store and in home, I couldnt even read the the numbers (very tiny numbers), so I couldnt check. And the drum machine it was not working directly connected to the speaker, he must have that end circuit. But, the synth works well without the filter. Thank you anyway.

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  5. I have a question it can interest others also. I really have no clue how to generate the patterns. I really would like to make my owns. Sorry my ignorance, I think it's the part with "B00100101", but no clue to this moment how to generate this part of the code. Thank you so much :) When I finish with a proper box, I will show if you are interested :)

    1. Hi Jo, I haven't really looked into the code yet (Jan Ostman wrote it not me!), but where it starts "B00100101" could well be where you could program a new pattern. If you look, there are 16 "B00100101"'s in one block of code, which is probably the 16 steps that make a drum loop. '0' is digital for off, and '1' is digital for 'on'. Elsewhere in the code you are shown the drum sounds;
      Patterns GU BG2 BD CL CW MA CY QU
      You can see there are 8 instruments that make a drum kit, and there are also 8 numbers in "B00100101"
      So it maybe possible to program the drum kit this way. Say if you just wanted the bass drum (shown as BD) to play and nothing else, you type "B00100000", or if you wanted no sounds to play: "B00000000". I'm only guessing this, so I could well be wrong! But it wouldn't be too hard to give it a try & if it doesn't work, just re-upload the original code and it'll work again. Let me know how it goes please! & yes, I'd love to see the version you've made. Thanks!

    2. Right you are Mr. Hoskins. The eight numbers in the line of code after the letter B represent the eight intruments and each line of code represents a pattern step. I've swapped out more than half of the stock patterns with old breakbeat patterns just for fun. "Take me to the Mardi Gras" sounds great on the MiniPops!

    3. Oh wow cool! I shall be adding my Gabba pattern to this ASAP! Thanks for letting me know ;-)

    4. Hi guys! I've been working out how to get round the limitation of one bar patterns on the Arduino Drum Machine.Eureka! Programme each bar in a different rhythm slot and with careful planning rotate the pattern knob at the right moment.16 different bar patterns should be enough for most people.
      I hope to build the ADM and String Machine soon.Great projects,more please!

  6. Your wooden box is amazing, how did you do the writings?

    1. The writing on the perspex? I used a banggood laser engraver, which you can read about here; http://bloghoskins.blogspot.de/2016/08/banggood-2500mw-laser-engraver-setup.html

  7. Very nice project. I try to bild it also, but instate of numbering the pattern from 1 to 8, I would like to use the names. But it is not easy to find the right name of the tokens:
    BD = Bass Drum
    BG2 = ??? (Maybe Bongo?)
    CL = Claves
    CW = ???
    CY = Cymbal
    GU = Guiro
    MA = Maracas
    QU = Quijada
    Could you help me to find the corret names?
    Thank you very much.

  8. God job it's nice project for musicians

  9. God job it's nice project for musicians

  10. God job it's nice project for musicians


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