Velocity Sensitive Cardboard Keyboard

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.

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

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.

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

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.

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

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

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

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.

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).

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.

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.

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

You need to download the "ToneAC" library from https://bitbucket.org/teckel12/arduino-toneac/wik...

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

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