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Instead of getting stuck in the same cycle every day, Jar of Change is here motivate you into taking the first step out of your comfort zone!

Problem Prompt

Introduction to Physical Computing 60-223

Professor: Robert Zacharias | Fall 2018

Programs Utilized: Arduino IDE

Create an assistive device for yourself. Observe various problems that plague you in your everyday life and brainstorm a device, using an Arduino, that would be able to solve that problem. 



Physical Prototying, Laser Cutter, Soldering Iron, Arduino, LED RGB Strips, LCD Display


Mirrored Acrylic, Mason Jar, Mylar Film, Copper Tape, Hall Sensor, Magnets


Try new things every couple of months. Work on specifically integrating this habit into my schedule.


Creating a device that encourages change in behavior with longevity, ease of use, and is effective, without annoying the user.


Visually appealing object that can easily be integrated into a bedroom and serves to encourage the user to reach personal goals.





In this project, one major decision point I faced was when I realized that the LED lights on the outside of the jar was too bright.


I experimented with a few different configurations and combinations, ultimately deciding  that the best combination was to put them on the inside of the jar. I used mylar film to cover the outside of the jar in an attempt to diffuse them and I’d hoped to create an interesting effect with the mirroring and diffusing of light. I was trying to achieve an effect similar to Yayoi Kusama’s work with infinity mirrors, in a much smaller scale.

Though it performed differently from my expectations, the reflectivity of the mylar had a visually appealing effect and it did manage to mute the LEDs to make them more pleasant to look at which was my main goal.


Jar of Change with lights on the outside



As a result of my decision to place the lights inside the jar, I had to figure out how to run the current from the outside of the jar where the Arduino and power supply is to the inside of the jar where the lights were when the lid is on. My professor advised I try using copper tape and though I had some frustrating first attempts, the lights were actually quite reliable after a while, as long as the lid wasn’t screwed on too tight.


Testing the copper tape with the mylar partially undone for better access to the wires on the outside



The second big decision point was when I was debating the design of the “box” to hold the Arduino and some other electronic connections. First I estimated the amount of space needed by testing it with some scrap cardboard.

After getting the measurements for that, I made some sketches of the initial design. I wanted to make the base a circle to match the shape of the jar. I had the thought of using the mirrored acrylic mimicking waves to reflect the light and attempt to amplify it’s effects/create interesting, non-standard views. I planned for the bottom to be made of two parts that could combine to form one piece or come apart in case something messed up with the wiring. I wanted holes to run both the data cable from the computer to the arduino and from the 5V power supply to the LEDs.

I first tried to Rhino model waves that would be made from stacked slices of mirrored acrylic. I was worried after a while about how much it would reflect facing up, how noticeable the wave effect would be, and how much mirrored acrylic I would be buying under the class budget (I didn’t want to waste too much money on something not vital to the functionality).


Testing the copper tape with the mylar partially undone for better access to the wires on the outside

Then I attempted to try a few different methods of making the wave, the most notable being one with slices that would rotate around the jar with acrylic pieces that laid on it to reflect the light back at the jar.  That method, though it would have been the most clear version of a wave, would have required at least a 2′ x 2′ piece of acrylic and didn't seem like it would produce the effective results in terms of light distribution.


The final design ended up being one where I surrounded the jar with mirrored acrylic pieces following the rough pattern of the etched ripples on the surface to give a slight field of mirrors effect. The taller pieces would be around the LCD screen, increasing the liklihood of the screen being reflected when viewing from across the room. This design explored the LEDs reflecting off the mirrors, resulting in an effect that was more successful on the brightest mode (rainbow lights) but still noticeable with the more subtle modes. 

Final Result


Of the numerous problems I tackled and solutions that I brainstormed, the one that I was the most enthusiastic about was stagnation from change. As a human being, I love change. One of the things I love the most about college is the change in activities and schedules between the days of the week and complete schedule refreshes every semester. I'm very aware of the fact that once college ends, my life will most likely become one of routine and stagnation from change. The purpose of this assistive device is to prompt me out of my comfort zone. It also serves as a version of a journal where memories are stored which I'm usually terrible at remembering to keep up to date. 


Similar to the jar full of memories that some people choose to keep and read at the end of a year, I've decided to create a jar of change. The concept is simple: the LED strip lights up the jar, which will be placed somewhere visible inside the user's bedroom. Every time the jar has been opened, that will have meant a note/picture/drawing/anything will have been placed in the jar as evidence of my "act of change". This can be in terms of learning a new skill, tackling a new self-assigned project, trying a new activity, meeting new strangers, putting yourself out there more, etc. What ultimately matters is that it will prompt the user to try new things that make their life more exciting. After a set period of time, the LEDs will flash through sequences of patterns to notify the user of the passage of time while still being visually interesting.


The settings are rainbow for the first month, sequencing with orange the second month, sequencing through red the third month, and flashing red the fourth month. The LED sequences and timing can be augmented in the Arduino IDE which uses C/C++ code. In reality, the durations should be tested to optimize the impact of the stages in influencing the user and the number of stages can be altered to create visible correlations between the lighting patterns and sense of urgency to change. Opening the jar causes the magnet on the lid to trigger the hall sensor, setting the timer back to zero. 


Default closed state

3 cups


3 cups


1 cup


Hall Sensor



Hall sensor, hiding behind the mylar film, reacts to the magnet attached to lid, sending a signal to the Arduino


LCD Display with encouraging messages and after enough time, suggesting new activities to try out

Mylar film hides LED wiring from the user


Jar of Change schematic

Next Steps




One problem I ran into was the implementation of the counter. The Arduino records time in milliseconds which adds up fast. Even the largest value of storage, unsigned long, only counts up to 4.2 billion. One day alone contains 86,400,000 milliseconds. I discovered after this project was complete that it would have benefited me to incorporate a real time clock which I will take into account if I decide to recreate/iterate further on this project. A real time clock connected to the Arduino would be able to record the last time that the jar had been opened and determine the state of the jar depending on how long ago that was. The real time clock also has the advantage of not losing count if the device is unplugged or a power outage occurs.


I would love to have been more intentional with the placement/cutting of the mylar. My execution served to achieve its objectives and had an interesting bandage aesthetic which was visually interesting in my opinion, especially in daylight with the lights off. 


Given time for exploration, I'd love to have tried other combinations of magnets and hall sensors so it's less visually noticeable. The hall sensor was pretty small but the magnets were visually noticeable. I would have preferred something more seamless/almost invisible.


The current container design plays with reflection and refraction of light from the LEDs/LCD screen to the user. Given more time, I would have liked to prototype some other designs, especially exploring more organic forms to compliment the curved sides of the jar. One aspect to experiment with is if there's a method that will increase legibility of the message, even when the user is across the room. Possibly incorporating a small projector, similar to a pico, that could be multipurpose.


Through the testing, I realized logistically I probably would not want this item to be on in my room all the time, especially if I was trying to sleep. It would serve as a wonderful nightlight but I personally prefer total darkness when trying to fall asleep. Logistically it would result in some testing whether an on/off switch would be optimal or a switch that served as a snooze button for a set number of hours (6+). It would also be interesting if it was based off realtime data (ex: stay on 6PM until my target bedtime. If I went with the on/off option, is there a way for the light to turn on so I don't forget about my goal without being disruptive?


Optimally I would enjoy if the LCD screen could be connected to some version of an online bucket list on Google Docs/Pinterest or could peruse the internet for seasonal activity suggestions specific to my city. Though in reality my phone could easily fulfill those purposes, it would be very convenient if personalized suggestions could appear on the display, tempting me to venture out of my comfort zone while being realistic and taking into account what I've already accomplished. I'm a curious person by nature so the most effective would be a self-updating list of items that are novel with a small description to peak my interest.

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