Convert a toy piano to work as a midi device and use it with Synthesia

Picture of Convert a toy piano to work as a midi device and use it with Synthesia
Goal of this project:
Convert a cheap toy piano to work as a midi device and use it with Synthesia (http://www.synthesiagame.com/)
Other programs that use midi inputs can also be used.

The pushbuttons of the piano are used to make a simple pull-down circuit for the arduino mega. The arduino interprets the keystrokes and sends serial midi data to the pc. Then this data is send to a virtual midi port with "serial-midi converter". This midi port is connected to Synthesia via "MIDI Yoke". MIDI Yoke is a driver that creates virtual ports. Each port has an input and an output which are connected. With MIDI Yoke you can couple different midi programs without any physical hardware.

Step 1: Parts and tools

Picture of Parts and tools
List of the parts needed for this project:

- Toy piano
- Arduino mega (This project van also be done with an arduino uno but you should use an line decoder to expand your arduinos inputs.)
- Flat ribbon cable (from old pc)
- Connectors (1 for piano and 1 for arduino)

List of tools needed: 

- Soldering iron
- Desoldering pump or wick
- Ohmmeter
- Hot glue or any other strong glue
nsljivic10 months ago

Any way to run MIDI Yoke on Windows 8+ ?

Luke7412 (author)  nsljivic10 months ago

I still use windows 7 and i hadn't any problems. On the midi OX forums they suggest to install midi yoke with "Windows User Account Control" turned off.


P.S. Don't forget to turn "Windows User Account Control" back on after the installation has completed.

The forum contains a lot of other helpful information concerning Midi yoke installation. http://www.midiox.com/cgi-bin/yabb/YaBB.pl?board=MYInstall

I hope this is useful.

nsljivic Luke741210 months ago

I havent seen your reply :D but i ran it with troubleshoot compatibility, used Test program, and installed it smoothly.. Tnx.
But i still have some trouble. I use Arduino Uno, (0-13 + GND) and an piano keyboard with 47 keys, and 15 pins input/output. I did every step, but SM's TX and RX flashes just once red, and nothing happens even when i press keys.. Maybe i should change the code in arduino? any hints? :D

Luke7412 (author)  nsljivic10 months ago

My arduino code is used on an arduino mega so it won't work on arduino uno. But the general structure is there. You should make a for loop over all digital input pins, read every pin and compare it to its previous state (stored in prevPinState). if there is a change: send a midi command. You also have to choose another "offset". this is used to convert the pin index to the corresponding midi key note number. (see http://newt.phys.unsw.edu.au/jw/notes.html)

Also make sure the indexes of "prevPinState" are correct.

FueGoDj1 year ago


Girts2 years ago
So,as I understand,i can use this not only for toy piano,but for whatever buttons I want,right?The red wire whitch isn't connected to the flat ribbon cable is the +9V Lead?
Thank You.
Luke7412 (author)  Girts2 years ago
You can use this for whatever buttons you want. I've seen a simular project where they used pieze sensors to monitor the strokes on a xylophone and convert these to midi.
The red wire is connected to ground. This is because i used the internal pull up resistors of the arduino. If you press a button, you will pull the voltage to ground. (Inverse logic: button pressed is LOW, button released is HIGH).
danjovic2 years ago
You can do this also with a Standard Arduino (UNO, Diecimila, etc) and a bunch of shift registers.
Luke7412 (author)  danjovic2 years ago
It should be possible. You will have to use extra hardware because these standard arduinos don't have a lot of I/O ports. The most obvious thing to do, would be to use a IO port expander (http://www.maximintegrated.com/products/interface/io_expanders.cfm). There also exist keypad encoders like the EDE 1188 (http://singlechips.com/pdf/ede1188.pdf) but I am not  sure you could use them for this application.