Experiment4_3 Crafting Electronics Swatchbook — The Music Box


Add some music to your little things in daily life.
Group #11
Rhepa Kamal
Ziqi Guo
Qinxinrui Zhu
Weiqi Wu

Wrok done by Weiqi Wu (3175842)


This is a Speaker Actuator. This is an interactive music box (speaker) that users could place their cup or anything that has weight. While something is placing on the towel part, the music will on. The inspiration comes from the process of making the speaker actuator in assignment 4-2. In this project, I tried to explore the way that collaborates the speaker with other things. During the exploration, I found out that there is a lot of stuff on my desk, therefore, I decided to combine the speaker with something so that it will save the space on the desk as well as people can have some music playing.


Function purpose: 
- Magnet
- Magnet Wire
- Arduino Uno
- Sponge
- Tin foil
- Adafruit Mono 2.5W Class D Audio Amplifier - PAM8302
- Tape and Glue

Decoration purpose:
- Foam Board
- Acrylic borad 
- Towel

Tool and Techniques

  • Utility Knife: To help to cut the form board and sponge
  • Scissors: Used to cut the magnet wire, tape, and tin foil
  • Double-sided tape: To set the fixed position
  • Glue gun: To construct the box and any other things that need to be glued

Materials and Tools


First Prototype

Construction Stages



(top-left: details of the class-D amplifier; top-right: detail of the Arduino Uno; bottom-left: the overall details; bottom-right: the magnet wire speaker)

This is the very first prototype of the speaker, testing if it is working or not.

Detail Shots



(upper-left: all the components inside the speaker music box; upper-right: the outlook of the music box; bottom-left: the magnet under the cup; bottom-right: the cup place on the music box, and the music box start to play music)

For the next step, I made a box for the speaker, and it became a music box. It connects all the wire and put it inside the box. On top of the music box, it is the magnet wire. The magnet is under the cup. So when the cup place in a specific area, the music will turn on.

Stage of Interaction


This is how the first prototype will interact. Placing the cup on the music box, and the music box will turn on.

Video of the First Prototype:


Circuit Diagram



For the first prototype, the music box could only interact with the cup. I would like to further develop it that no matter what objects people place on the music box, there will be music playing. Therefore, I need to put the magnet in the music box at the beginning. To solve the problem that the music will always be playing, I decided to find a method that can open the circuit before the input of the magnet wire. Therefore, only when something place on the music box and close the circuit, the music box will on.

Second Prototype

Construction Stages


I used Velostat to test whether it will work or not. If it works when the object places on the music box, there is pressure on the Velostat, and the circuit will close, the speaker, which means the music box, will work. However, the Velostat does not really work, there is no sound. So fail to use Velostat as the switch to the circuit.

Final version

Construction Stages

With the inspiration of my group member’s example in assignment 4-2, which called “Three Buttons”. I decided to use sponge and tin foil to create the switch of the circuit. So when the object places on the music box, it will add pressure to the sponge, and two sides of the tin foil will touch each other which closes the circuit.



(top-left: the sponge that cut; top-right: the sponge with two sheets of tin foil; bottom: the sponge with the tin foil in two sides)

Video of Testing:  https://youtu.be/EAUNLButh_E

It does work really well. So I started to construct the music box and make the sponge looks better.



(top-left: foam board of the box; top-right: cover the sponge with a towel and testing whether it works or not; bottom-left and right: finish making the box. The towel is on top of the box, and there is a foam board on top of the sponge, in order to make it looks better.)

These are the construction steps of making the music box. However, it does not work, the foam board on top of the sponge is too supportive. It spread the weight of the object, thus, there was less pressure applied on the sponge, which not allowing tin foil to connect together.


(top-left and right: I decided to leave only the sponge with the towel cover on top of the box since there is no better option for me to do that)

In this way, the speaker will work when there is pressure on the towel area.

Detail Shots


(left: the overall look of the music box; right: the overall looks inside the music box, including the paper speaker, magnet, amplifier, and Arduino Uno)

Stage of Interaction



This is the stage of interaction. I placed a cup and a candle on the music box, and it works properly. The music box will on and play some music.

Final version VIDEO

For the video of the final version, the amplifier experienced damage before the video recording, which made it does not work anymore. There two possible reasons that the amplifier became broke. The first one is that the amplifier experienced a short cut. It was too hot during the testing that burned inside, so the amplifier does not work anymore. Another reason is that I used a glue gun to fix the position of the amplifier and the hot glue was directly applied to the amplifier, and the glue was really hot, which might lead to damage to the amplifier.

Before I found out that the amplifier is broken, I test different parts to check where the problems happen. I made a new paper speaker and used a new wire to connect each part. Then I reupload the code to the Arduino Uno. And after that, I built the basic version of the speaker, and it still did not work. So I think that the problems happened in the amplifier.

Since I only have one amplifier and buy a new one will take at least two weeks to deliver, I could not record the video of the final outcome of the music box. But it worked well when I took the photos of the stage of the interaction. At the interaction stage, I haven’t use the glue gun to fix the position of the amplifier. In the interaction stage, before I put anything on the music box, there is no sound or music, and after I place the candle or cup on the towel area on the music box, the music box started to work and play music.

For the basic working principle understanding, the testing video is basically the same as the testing of the final version, other than the extra towel-covered on the sponge and set on the music box. So please look at the testing video and find out how the music box work.

This is the testing link: https://youtu.be/EAUNLButh_E



Reference Code Link: 

I used the reference code in the project. However, people could change the sound into a song, or connect it to a cloud or Spotify to play a playlist.

Reference Source: 



Due to the accident of the broken in an audio amplifier, I think that it would be better next time to add a resistor in between the speaker and the amplifier. During the testing, the amplifier was hot while using it, so that might be the reason for burning the amplifier and made it doesn’t work. Also, another reminder will do not put anything too hot on the amplifier or other microcontrollers, which might cause some damage because of the high temperature. In addition, in order to allow the project to work smoothly, it is a great idea to prepare at least two sets of materials so that when something is not working, there will be another one for you to continue your project.

For further development of this project, I would like to change the material for making the music box. Instead of foam board, it will have better look in wood, acrylic board, or metal. Also, I would like to change the sound of the music box that makes it into a song instead of only some notes.

Moreover, people could add more colours to the music box if they want to. I like a white and clean look, so I did not add any colours.

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