Creative Programming for Digital Media & Mobile Apps

I’m doing this Coursera course at the moment: Creative Programming for Digital Media & Mobile Apps. Fun stuff! For the 2nd week peer review assignment I made this in Processing. I wrote the music for this, and found the video footage on archive.org. The harder I blow on my instrument, the faster the lady moves. And those circles in the background also respond to breath (bigger for louder).

Written by moshang in: DIY,Technique |

Groovesizer mk1 Manual

You’ve built a Groovesizer mk1? Awesome! Here are the operating instructions for firmware V0.19.



Pick-up:  The pots perform a number of different functions. To avoid sudden jumps to new values when the pots are turned, values will only change once the pot has passed through its currently stored value.


  • pot 1 – grain 1 pitch
  • pot 2 – grain 2 decay
  • pot 3 – grain 1 decay
  • pot 4 – grain 2 pitch


  • but 1 + pot 1 – 4 – note entry for steps 1 – 4
  • but 2 + pot 1 – 4 – note entry for steps 5 – 8
  • but 3 + pot 1 – 4 – note entry for steps 9 – 12
  • but 4 + pot 1 – 4 – note entry for steps 13 – 16
  • rests – turn the pot all the way anti-clockwise
  • ties – turn the pot all the way clockwise
  • multiple notes can be edited at the same time by holding down more than one button


  • pattern length – adjust the length of the pattern (1 – 16 steps) with the control pot (no buttons pressed).
  • tempo – adjust the tempo with shift + control.
  • note duration –  adjust the duration of the notes with shift + pot 4.
  • swing – adjust the amount of swing with shift + pot 3.
  • tap tempo / retrigger – retrigger the pattern with shift + but 4. Multiple taps will adjust the tempo.
  • reverse – reverse the playback direction with shift + but 3.
  • transpose up – transpose the pattern up a semitone with shift + but 2.
  • transpose down – transpose the pattern down a semitone with shift + but 1.


  • enter/exit pattern mode  – hold but 1 and press shift (not to be confused with transpose down – see above)
  • bank select – choose a bank from 1 – 8 with the control pot (no buttons pressed)
  • store – press and hold any one of but 1 – 4 until all the leds blink on and off. Press the same button again to store the current pattern to that location, or any button to exit .
  • recall – press but 1 – 4 to recall any pattern saved in that location for that particular bank. By default, the selected pattern starts to play as soon as the end of the current pattern is reached (quantized).
  • immediate recall – to start playback of a selected pattern immediately, hold down shift when selecting the pattern with but 1 – 4.

And that’s it – have fun!


Groovesizer mk1: DIY 16-step sequencer and synth



This project has evolved substantially – follow developments regarding the Groovesizer DIY kit at groovesizer.com. To distinguish this project from the kit, this one has been rechristened Groovesizer mk1.

I’ve attached a 16-step sequencer to the original Auduino lo-fi synth and have added 8 LEDs and 5 buttons to the original design, and thus the Groovesizer is born. You can download the Arduino sketch here Groovesizer Arduino Sketch (v0.19). And here’s a breadboard schematic:


You’ll see I’ve maxed out all the ins and outs of the Arduino. I feel I’ve pretty much reached the limit of features I can support with the buttons and knobs available. For a future version, I’ll get into multiplexing to add more buttons, maybe an LCD, and while I’m at it 8 more LEDs.

Here’s the current feature list:
– note entry for individual steps or groups of up to 4 steps at once
– rests & ties
– pattern length from 1 – 16 steps
– pattern retrigger
– tap tempo
– pattern reverse
– pattern transpose (up and down in semitones)
– variable note duration
– swing/shuffle
– MIDI out
– save and recall up to 32 patterns
– trigger patterns quantised (Ableton live style) or immediately

Here’s the link to the MANUAL.

By the way, I wanted to reclaim my Arduino for future projects and make this one permanent, so I replaced the Arduino with a hackduino, following this recipe. It works a treat. I’m considering having Groovesizer PCBs made that incorporates the hackduino. Anyone besides me interested in something like that? Leave a comment.

Latest Firmware:
Groovesizer mk1 – v019 – incorporates DuaneB‘s volatile fix

UPDATE 2 (2013-12-08) – Frontpanel Design

Splendit bend it did a nice demo on his SoundCloud page and also designed this cool frontpanel. Thanks for sharing, Splendid!
Frontpanel – png

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