Velocity Sensitive Cardboard Keyboard




Introduction: Velocity Sensitive Cardboard Keyboard

About: I like technology, innovation and creativity. Follow me on social networks @ivansarmientoproyectos

Hello, in this tutorial I wanted to take advantage of the only piece of cardboard that I had in my whole house, because of the quarantine I couldn't get more, but I don't need it! With a small piece we can do interesting experiments.
This time I bring you a Velocity Sensitive Cardboard Keyboard that works with proximity IR sensors. Depending on whether we play a piano key faster or slower, the musical note will sound more or less hard, respectively.

Step 1: Materials

For Hardware

  • Cardboard sheet, only 55 cm x 25 cm needed
  • Scissors or scalpel
  • Hot silicone gun
  • Gray, white, black paint (optional)
  • Brush (optional)
  • Aluminum rod 5 mm in diameter and 16.3 cm long
  • Instructables sticker (optional)
  • Pencil, pen or sharpie
  • Ruler
  • Rubber strips or some elastic material
  • Sewing machine
  • Tweezers

For Circuit

  • Arduino, I used Arduino Mega 2560
  • 5 10k Ohm resistors
  • 1 1k Ohm resistor
  • 1 100 Ohm resistor
  • Cable
  • 1 buzzer
  • 5 reflective IR sensors, I used QRE1113
  • Universal pcb
  • Battery (optional)
  • Soldering iron
  • Tin
  • Caiman-caiman cable

Step 2: Cut Cardboard Pieces

Cut all the cardboard pieces with the dimensions shown in the image, I did it using a ruler and scalpel because I did not have access to a laser cutter, however, I also attached the vector file so that you can easily cut it by laser machine.

Step 3: Make the 5 Piano Keys

Join the pieces of each piano key using hot silicone, as shown in the images. Repeat the process 5 times.

Step 4: Make the Piano Base

Join the pieces of the piano base using hot silicone, as shown in the pictures. The base is made up of the drawer and the cover.

Step 5: Paint Everything With Your Favorite Colors

I decided to paint the piano keys white, as they traditionally are, and the piano base gray to perfectly match the Instructables logo.

Step 6: Locate the Rubber Straps

The rubber strips allow the piano keys to return to their original position, locate them as I show in the images.

Step 7: Paste the Sticker (decorate)

At the end of this stage, you should come up with 3 main parts, the cover, the base and the keys of your piano.

Step 8: Construction of the Circuit

The circuit is designed with Arduino, you can build it as you see fit, the following steps are tips describing the way I did it.

Step 9: Cut Universal PCB and Solder

The sensors that I used are SMD, therefore I need a PCB to solder them on, cut 2 x 3 hole rectangles from universal PCB. And add tin to the 4 holes at the ends to be able to solder the IR sensor (see images).

Step 10: Solder Cables and Resistors

To avoid further complications, I decided to solder the resistors directly to each other so that I could insert them all into the Arduino. Finally, I soldered all the cables guiding me with the fritzing design.

Remember to check your circuit connections with a multimeter.

Step 11: Insert the Keys Into the Aluminum Rod

Insert the 5 piano keys into the aluminum rod and the rubber strips into the corresponding holes.

Sew together the rubber strips to the base of the piano.

Step 12: Upload the Program to the Arduino

Connect the Arduino of your piano to the PC and program it with the attached file.

You need to download the "ToneAC" library from

Step 13: Connect Battery

Finally, connect a power bank to play piano in the place you prefer!

Step 14: Result

I hope that you all enjoyed this Instructable! Thanks for reading and watching.

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    2 years ago

    I made this for our classroom. The children will be absolutely delighted when they get back!
    Than you for making this, i95sarmiento


    Reply 2 years ago

    Thank you very much Ginny76, it makes me feel very honored to know that you use my project in your classroom, that is the best award you can give me.


    Reply 2 years ago

    It's my pleasure.


    2 years ago

    Super great! And portable.


    Reply 2 years ago

    Thank you! I already planned version 2 of the piano, much more compact and modern. I'll post it when I build it.

    Penolopy Bulnick
    Penolopy Bulnick

    2 years ago

    This is a really fun idea :)


    Reply 2 years ago

    Thanks Penolopy! It will always be a pleasure for me to share my ideas on Instructables.

    Penolopy Bulnick
    Penolopy Bulnick

    Reply 2 years ago

    That is great to hear :)