Sound/Light Hat

  • Concept
    • A hat that sensors music and neopixels brightness go up and down according to the music volume. A capacitive touch sensor that turns the hat’s lights on and off. 
  • Parts List
    • Flora RGB smart neopixel version 2 – sheet of 20
    • Conductive thread
    • Circuit playground express
    • Conductive fabric
  • Process
    • I first started by making a drawing of the hat and how I wanted it to look. I was also unsure about where to place the neopixels, so this drawing has them at the top and bottom. It also has a capacity touch sensor to turn it on/off.


I also researched the flora neopixels, since they have to be placed in a specific way and a small mistake, like not following the arrows can ruin the lights.


  • Circuit Diagram
    • This is what the circuit would look like. The positive is connected to “VOUT”, the negative to “GND” and the lights to “A1”. The lights have arrows that have to be followed for the circuit to work.


  • Code
    • This code changes the brightness of the lights according to the sound of the environment. The lights have a random colour, which means they are always changing colour and the brightness is the only thing affected by the sound. The capacitive touch turns off the lights.


  • Final Project Images 
    • Inside
      • The inside of the hat has extra felt to make sure the thread isn’t visible on the outside. I use tape for the prototype because at the time my circuit wasn’t fully functional.

img_7281 img_7282

  • Outside
    • The outside of the hat is very minimal, I thought of adding an extra layer to diffuse the lights but decided not to since I liked how the neopixels looked and because this is more like a party hat diffusing the lights isn’t necessary.

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  • Reflections & Next Steps
    • I think my stitching wasn’t the best, therefore the lights wouldn’t turn on every time. If I do closer and stronger stitching it would work, so for the next step, I’d like to re-do the stitching and find a new way to hide the sticking from the outside of the hat.
  • Resources & Related Works
    • Core Electronics. (2018a). Circuit Plaground – Colour Matching with MakeCode [YouTube Video]. In YouTube.
    • Core Electronics. (2018b). Sound Reactive Lights Project with Circuit Playground & MakeCode [YouTube Video]. In YouTube.
    • (2020, September 23). NeonDancer 9000.; Hackster.

Capacitive Touch Piano

  • What is the Felt/Capacitive Piano?

It is a soft circuit device that acts as a makeshift piano by using the idea of capacitive touch to create output. In this case, the output would be a sound/tone similar to that produced by a piano. We wanted to share such a product to explore how soft circuits can be combined with musical concepts that can dwell into a myriad of soft circuit devices and wearables and as well a method of creating music.

  • Materials Used & Where to Find Them
Black & White Felt Michaels, Dollarama
Conductive Fabric Class kit, Creatron Inc
Conductive Thread Class kit, Creatron Inc
LED lights Class kit, Creatron Inc
Resistors Class kit, Creatron Inc
HeatnBond Lite Iron-On Adhesive Michaels, Amazon
CPX Class kit, Creatron Inc
  • The Design


With the black felt, cut a rectangle for the base of the piano. With the white felt, cut smaller rectangles for the keys.


First, cut out the size you need for the keys. Then, use an iron to heat and bond the adhesive to the bottom of the keys. You can also use glue or regular thread to do this.




Peel off the sticker and use the HeatnBond Lite Iron-On Adhesive in the back of the fabric to glue the white keys onto the piano.


Use an iron to glue the now adhesive side of the keys onto the base of the piano. 


Cut smaller pieces of conductive fabric and glue them either using the same HeatnBond Lite Iron-On Adhesive method or using regular glue or non-conductive thread.  Add LED Lights on top of each key, either poking them through or using a regular thread. (The conductive thread will be used when adding the CPX!)

After writing your own code and making a circuit diagram, place the CPX under the base, and use conductive thread to sew the keys and LEDs to each of their respective pins. 

  • The Circuits & Code


The sensors are the keys with the conductive fabric on them. Using conductive thread, in this diagram presented as wires, we connected these capacitive sensors to pins on the CPX. Also connected to pins on the CPX are our LED lights, in this diagram we only show one but there are four in total, the same amount of keys we have on our piano.


With this code, each of the pins is set to play a tone on the CPX when activated. They will be activated when someone touches the ‘keys’. 


When the keys are touched, their corresponding LED is also activated. For example, you’ll see in the block of code on the left, it states that when pin A6 is activated, pin A3 will also be activated.


First I started by using if and else statements. But due to it being a one-time click event, the LEDs wouldn’t change. I tried to counter this by declaring other led pins low while 1 was high, but this only further complicated the situation.

screen-shot-2022-03-17-at-8-40-08-pm screen-shot-2022-03-17-at-8-40-15-pm

I then went on to implement a button “down” and “up” function. I used “pin” to define the analog pins and within the “down” segment I set a melody and set the pin (A3) to high to turn on the external LED.

In the “up” segment where the capacitive sensors would obtain no pressure so I set the sound to “stop all sounds” and set the pin controlling the external LED to 0. This still was inefficient at activating the LED. Once I changed “pin” to “touch”, the capacitive sensors were outputting through the LED and the Adafruit speaker. 

  • The Final Code


  • Our Completed Prototype!


  • Reflection


Have the circuit in hand before starting the design. We accidentally made a design that didn’t work with all four LED lights because we didn’t have an idea of what the circuit should look like before we began.


If you decide on using the HeatnBond adhesive, make sure to research which materials you’re using before using an iron. One of the materials we used ended up burning a bit when the iron was applied to it.

  • Similar Projects
  • Team: Manuela Ballesteros Pinto, Ronit Sharma, Laila Mariam Imran.

Expressive Wearable Assignment – Manuela Ballesteros

  • Concept

For this project, I chose the feeling of being in a rush, I wanted to make something that would help those who are constantly stressed to take things slow. This armband has a photoresistor that is used as a proximity sensor which will use sound and light to let the user know when they’re about to hit something/someone. The sound and lights become louder and brighter the closer the sensor gets to the object. It also used a motion sensor that will make a sound when the person is going too fast.

  • Objective

The objective is to try to make people be more careful, the city can be very fast-paced and everyone seems to be in a rush which can cause accidents.

  • Process
    • Diagram


The first thing I did was the circuit diagram.

  • Testing


Tested the circuit using alligator wires.

  • Code


Made the code and tested it multiple times using the wires.

  •  Parts list
    • Conductive thread
    • Photoresistor
    • 10k resistor
    • Felt
    • Thread
    • Circuit Playground
  • Final Prototype 

img_6531img_6530 img_6534img_6536 img_6537img_6539


  • Reflections

One thing I would’ve done differently was the use of a different fabric, something that would allow me to test the motion sensor with the armband without the photoresistor moving around and triggering the proximity sensor.

  • Sources

Adafruit Circuit Playground Express – Loudness Necklace / Javascript editor. Adafruit Circuit Playground Express – Blocks / Javascript editor. (n.d.). Retrieved February 28, 2022, from

Best running arm bands for 2022: Sports illustrated review. SI. (2022, February 15). Retrieved February 28, 2022, from