Build your own MIDI circuits
Frequently Asked Questions.
MIDI & Music
MIDI and Music Information

MIDUINO MIDI Random Player

The MIDUINO is a combination of MIDI (Musical Instrument Digital Interface) and the Arduino, which is based around the ATmega168 microcontroller. The Miduino is a breadboardable Arduino clone, and it comes with an ATMega168 pre-loaded with bootloader.


The board is designed with a built in Opto-coupler and 4-way DIP switch which allows MIDI IN and easy setting of MIDI channels (1-16) if required. MIDI out Note ON/OFF data is randomly generated, which can be constrained to certain notes and scales.



midi_boarduino_IN_OUT.jpg (609410 bytes) MIDI Random Player 


PRICE:  €35.00




Circuit Schematic:

A circuit schematic of the Miduino shows the Input/Output connections. A MIDI switch on Pin D12 can set the MIDI output to 38400 Baud to use MIDI via a FTDI USB 232-TTL cable utilizing the Roland MIDI Drivers or it can be set to the standard 31250 Baud for external MIDI DIN connectors.

This clone acts just like an Arduino,  it is programmed with the Arduino bootloader, so it can talk to the Arduino software and run sketches just like the original.  


USB Cable:

 This design does not include a USB chip, it is designed to use a FTDI USB 232-TTL cable to program the microcontroller.  However since the cable plugs directly into the Miduino, you can use one cable for multiple Miduinos.





     *Click to Enlarge*

The MIDI IN and OUT connectors use  5-Pin 180 degree DIN sockets. Note that the MIDI IN/OUT wiring is polarised and the correct pins should be used.





midi_boarduino_PINS_wiring.jpg (191151 bytes)




Note, because the MIDI IN Opto-coupler shares the same serial input as the USB interface, when programming the Miduino the MIDI IN connection has to be disconnected.



Miduino Specifications:

  • Designed , to plug into a breadboard, connect to external 0.1"  matrix boards or connect via female connectors for easy prototyping
  • Size, only 4" x 1.5" (100mm x 40mm)
  • Pins brought out are, Digital 0 thru 13, Analog 0 thru 5, ARef, 5V, Ground
  • Chip comes preprogrammed with a "no-wait" Arduino bootloader
  • 2 red LEDs, power and "pin 13" just like the Arduino Diecimila
  • Available as a low cost kit with standard parts,
  • All through-hole parts are easy to solder
  • ATmega168, utilizing a 16.00 MHz crystal,  like the Arduino Diecimila
  • Standard 2.1mm DC jack (just like the original) with 5V regulator to run on 7V-17V power
  • 1N4001 diode protects against using incorrect wall adapter
  • 2-pin header for MIDI IN
  • 2-pin header for MIDI OUT
  • 6-pin header at the end for a USB-TTL cable
  • Auto-reset capability when used with a USB-TTL cable


There are some differences between the Miduino and the Arduino. Shields cannot be used as the form factor is different

There are also no rx/tx LEDs and no rx/tx 1K series resistors.



Arduino is an open-source physical computing platform based on a simple i/o board and a development environment that implements the Processing/Wiring language. Arduino can be used to develop stand-alone interactive objects or can be connected to software on your computer (e.g. Flash, Processing, MaxMSP). The open-source IDE can be downloaded for free (currently for Mac OS X, Windows, and Linux).