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NEW REAL Final Project Documentation (Much better formatting) (1)

Page history last edited by Sunayana 6 years, 1 month ago

Design Background


People need both music and stress-relief squeeze balls to reduce their stress. If we combine these two functions into one device, and MP3 player that works based on squishy-ball input, we can create a product that people need.


  • When observing people listening to music around campus, I found that many looked especially stressed. The ones who looked the most stressed seemed to be listening to the loudest, most “heavy” music

  • While I personally don’t use stress-reliever squishy balls, I noticed that when I am stressed do listen to louder music, and subconsciously squish a pillow or another soft object—I saw then that the two actions are very related responses to stress

  • When my grandma was given a brand new phone with an MP3 player inside last month, she was so worried about all of the complicated functions on the bright LCD screen, and eventually just using the phone left her so frustrated and stressed that using music to relax was impossible. I also saw the same aversion to digital devices in my parents after a while, so I decided to design a device so simple to use that it wouldn’t even need an LCD screen and would not look digital at all (and therefore not look intimidating)

All of these observations made it clear that there was a need for a device that looked as un-digital and un-complicated as possible, that could play music and change something about the music depending on how hard the user squeezed the attached squishy-balls. My design goal was to create such a device that combined these two stress-relieving functions, and with such a simple interface that even my grandma would not feel stressed using it!

My player prototype at this point is still on a breadboard, partly due to time constraints that prevented me from transferring on to a perfboard, and also due to the fact that I did want to add other functionalities to this in the future which would have been much easier to change on a breadboard than a soldered perfboard. Also, because this MP3 player was not meant to be particularly portable (at least not this prototyping stage), perfboarding was not a major concern in the design process. However, it is definitely something that I would consider in the future.


The only three “inputs” that my device has are an on/off switch, and two squishy nodes to pause/play and fast forward, changing the volume of the song while performing those functions depending on how hard the user squeezes (how stressed they are). The idea being, of course, that the more stressed people are the louder the music they would like to hear. If they are tired on the other hand, and don’t squeeze hard, softer music will play.


Design Requirements:

My MP3 player should be…

  1. Simple to use

  2. As anti-digital as possible

  3. Fun to squeeze (like the stress reliever squishy balls, users should feel like squeezing the nodes)

  4. Fairly portable, in that it should not have to be connected to a computer constantly

  5. Fairly sturdy in the face of hard squeezing

Based on all of these deign and durability requirements, I decided not to make my entire player squishy (the electrical components would break and hurt people who were trying to relieve their stress), but instead have a hard casing with squishy nodes on it.



The electrical components that I am currently using include:

  1. Arduino Micro

  2. Breadboard

  3. Mp3 decoder

  4. SD card

  5. 2 FSRs (for sensing the amount of pressure users are squeezing with)

  6. Switch (power on/off)

  7. Standard AA battery with 5 volt step-up

  8. SPI Bus

I am also planning to use Bluetooth for extra functionality once the device becomes smaller and more portable.



My casing for this MP3 player was a laser-cut box that I designed in SolidWorks and Adobe Illustrator. My material choice was Duron, which I preferred to plastic or wood because of how aesthetically pleasing it looked alongside the purple velvet squishy balls that I had made, and also because of its durability (the most important feature for this prototype).

Mind Map:


State Diagram:

Verplank Diagram:

Paper” prototype:

My first prototype was made of foam, to imitate the “squish” properly. As you can see, my initial idea was of one squishy “blob” with an FSR inside, but I decided against this since my electrical components inside would either be too hard and hurt the user, or get squashed.


Building process:

My working prototype on the breadboard with one FSR attached. At this point, the pause/play interrupt was working properly and changing the volume according to the pressure of the input. (Please ignore the funny rose that just decided to take center screen )

This is a photo of my box as it came out of the laser cutter after I had designed it.


My finished, assembled box that already has one squishy node attached and the other FSR shown, as well as the on/off switch.



Image showing how I placed the memory foam to cover the FSR at protect it to a certain extent. I later sowed the opening closed to secure the FSR in place.


This image shows the pouches that I sowed and the extra polyester filling that I used along with the memory foam to secure the FSR and make the squeeze feel stress-relieving.

This images shows an issue than came up frequently when trying to solder FSRs—they two leads would be strained to the point where they would split and break off, rendering the FSR useless. I tries to use female headers on the leads and solder those to the wires, and that met with moderate success. However, the female headers did have a tendency to come off after some time, and re-opening the squishy pouches to fix this issue was a pain. So to anybody wishing to recreate this, using female headers with some kind of adhesive to make sure they don’t slip may be the best option.


Finished product:


Working final product, with foam and FSRs but without casing:  http://pressplay.pbworks.com/w/file/84242809/Completely%20working%20but%20without.mp4


Laser Cutting Process for box:





Comments (1)

David S said

at 7:27 pm on Aug 19, 2014

This is a fun, creative idea, and was quite nicely executed, despite the challenges that you faced in building it (code and wiring). Well done!

We like that you found an underserved need by observation and experience. The story about your grandma really helped to highlight the use case for your mp3 player. We also like that your final design addresses those needs directly.

In your Design Background P.O.V., we wish that you had remembered the distinction between needs and solutions: needs are verbs (“someone needs to relieve stress”), while solutions are nouns (“you relieve stress by squeezing squeeze balls”). We don’t create products that people need; rather, we create products that address people’s needs.

Your Verplank diagram includes and interesting metaphor about viewing signs rather than words. We like that this is a domain very different from listening to music, and wonder if a comparable stress-relieving tradeoff exists between images and words.

We like that you outlined a set of design requirements, always good to see. At the same time, we wish that the requirements were more specific and called out details required to fabricate the device. So for a player to be “simple to use,” would it have large buttons (what size), few controls (which ones), or few operating states (which ones)?

The description of the housing is complete, including materials and rationale, and we wish that you had included your Solidworks/Illustrator files.

We like the way that you describe and overcame your FSR soldering issues. You spent several days debugging your sketch to track the peak force and wait before checking again. It would be good to describe that challenge/solution as well, and to see your full code listing included, so others could learn from your approach.

Overall, we really like your project, and encourage you to keep iterating on the design until you have it close to your original vision.

Best Regards,
David, Nik, Samyuktha, Jane and Xinyi

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