How to make a MIDI piano with the Touch Board
Discover how to make a MIDI piano with the Touch Board
The Touch Board has a powerful MP3 decoder chip that can also decode MIDI notes from its onboard MIDI library, which is capable of playing multiple samples simultaneously. This way you can create and play your own MIDI instrument. To use the Touch Board’s stand-alone MIDI functionality, also known as real-time MIDI mode, you have to make some physical changes to the device with Electric Paint. You can either paint your own piano sensors with Electric Paint or use the sensor from the MIDI Instrument Bundle.
If you haven’t set up the Touch Board with Arduino before, please do so now.
Step 1 Solder the MIDI solder bridges
In order to use the onboard MIDI functionality, you need to connect two solder bridges on the Touch Board. If you want to go back to MP3 playback mode and play MP3 sound at a later stage you will need to remove these solder joints. You can cold solder the bridges with Electric Paint by applying a bit of Electric Paint on the two MIDI bridges.
Leave the Electric Paint a couple of minutes to dry.
Step 2 Attach the board to the keyboard
The electrodes of the Touch Board are simulating the piano keys and you can use any conductive materials to connect to the electrodes. For this tutorial, we are using a printed sensor that has 12 piano keys, screen-printed with Electric Paint, for our piano instrument.
To attach the Touch Board to the keyboard you can either use carbon dots or cold solder the device with Electric Paint. Carbon stickers aren’t as stable Electric Paint but don’t require any drying time, whereas Electric Paint requires a couple of minutes.
For the carbon stickers, peel the white back off the first carbon sticker. With the back removed, take the keyboard stencil and attach the carbon sticker to the end of the first key, by pressing it down through the plastic. Make sure to centre the carbon sticker onto the round node at the end of the key. Repeat the process with all 12 keys of the keyboard. Then, attach the Touch Board, carefully aligning the electrodes of the Touch Board with the carbon stickers.
If you want to cold solder the Touch Board, please have a look out our cold soldering tutorial.
Step 3 Upload the MIDI code onto the Touch Board
When the paint has dried and with the board attached to the piano keys, it’s time to upload the MIDI code to the Touch Board. Connect your Touch Board to your computer with the USB cable and turn the device on. In the Arduino IDE, go to
File→Sketchbook→Touch Board Examples→Midi_Piano
Make sure to select the correct Board and Port settings before hitting upload. If you haven’t set up the Touch Board with Arduino before, please do so before.
Step 4 Plug and Play
When you have uploaded the code, take a speaker or headphones, and connect it to the Touch Board. Try playing the keyboard on the paper, you should hear a sound when you touch a key. Enjoy playing the MIDI piano!
Step 5 Try other instruments
The MIDI code is set to “Acoustic Grand Piano” by default. If you want to try out a “Electric Grand Piano”, simply change the instrument number at the beginning of the code. If you change the scale, change the numbers in the array “MELODIC_NOTES”. On the other hand, if you want to try the drums, set the boolean “MELODIC_INSRUMENT” to “false”.
You can also try out the different sensors. Detach the Touch Board from the piano carefully and attach it to a different like described in Step 2.