Arduino MIDI Synth with LFO, Portamento, and Pitch Wheel

by nshaver

Published on December 28, 2014

This projects uses the littleBits Korg synth, the Arduino module, a USB MIDI controller, a powered USB hub, and an iPad running the MIDI Bridge app for MIDI routing. It supports pitch bend, LFO via the modulation wheel, portamento/glide via a MIDI CC, and on-the-fly MIDI channel changing. It is designed for live use, and is installed into a homemade synth platform using velcro'd littleBits mounting boards.

How To Make It


Gather all parts - littleBits synth kit, Arduino kit, powered USB hub, iPad, Apple Camera Connection Kit, MIDI Bridge iOS app, USB MIDI controller


Assemble a littleBits synth, test it using the littleBits keyboard, make sure it works.


Install the ARCore USB MIDI library into your PC/Mac/Linux computer's Arduino installation. Program the littleBits Arduino with the code attached to this project. The ARCore library is here: https://github.com/rkistner/arcore Insure that your Arduino can be programmed, and you should have the "Arduino Leonardo (arcore iPad compatible" board selected. If you don't see that board option, you haven't got arcore installed into the right directory tree.


Install your programmed Arduino into your littleBits synth, probably in place of the littlebits keyboard. The power module plugs into the left of the Arduino, and the synth plugs into the D5 output of the Arduino. The D5 output should be switched to its "analog" setting.


Connect all USB devices to your powered USB hub: Arduino via its included USB cable iPad via Camera Connection Kit USB MIDI controller keyboard


Start the MIDI Bridge app on your iPad, and connect your USB keyboard to the Arduino within MIDI Bridge. When you play keys on your keyboard on MIDI Channel #1, the line between your keyboard and the Arduino within MIDI Bridge should flash, and your synthesizer should play.


If desired, change the MIDI channel by playing a note between C1 and B1. C1=Ch#1, C#1=Ch#2, D1=Ch#3, etc... all the way up to B1=Ch#15.

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