Tag Archives: loopMIDI virtual port

This xylophone is powered by an Arduino Uno

A Maker by the name of LaurenCallahan has created an Arduino-powered xylophone.

More specifically, the xylophone uses an Atmel-based Arduino Uno (ATmega328) and multiplexer to identify when one of 8 keys are struck – playing the selected sound via MIDI on a PC.

Aside from the Uno, key project components include:


9 V battery with Arduino adaptor
  • Arduino to USB connector
  • 8 piezo disks
  • 8 1 M Ohm resistors
  • Protoboards (two separate)
  • Terminal connectors
  • Strips of acrylic and a box (or something to make the xylophone with)
  • Plenty of wire 
16 LED lights (two for each bar, cannot be more than two)
Suitable resistor (Maker used 220 Ohms)

“The multiplexer is key to this project, as it allows you to take 8 analog ins or outs, as opposed to the 6 on the Uno,” LaurenCallahan explained in a recent Instructables post.

“Using one analog in and three digital ports on the Arduino, the multiplexer runs through each input and reads any changes. In this case, the multiplexer reads any change in the piezo disks.”

On the software side, LaurenCallahan uses the Arduino IDE, hairless serial to MIDI converter, MAX MSP, Max Patch and the Arduino MIDI Library. After uploading the appropriate sketch, LaurenCallahan recommends opening Hairless, the MAX patch, the “Audio MIDI Setup” on OS X or creating a loopMIDI virtual port.

“After opening Audio MIDI Setup, go to Window–>Show MIDI Window. Make the selections shown in the second photo in the IAC Driver Properties window, assuring that ‘Device is online’ is checked,” she added.

“Return to Hairless, find your Arduino in the left-hand drop down window, unselect ‘Serial MIDI Bridge On,’ and choose the two options in the photo for the MIDI In and Out. Arduino will not be able to upload anything to the Arduino Uno if the ‘SerialMIDI Bridge On’ option is checked, and your computer will likely crash, so this step is very important.”

Interested in learning more? You can check out the project’s official page here.