Inspiration
We were inspired by the uncertainty faced by new drivers trying to gauge their speed and trying to adjust it to a reasonable range without looking at the speedometer. We were also inspired by the recent uptick in wearable electronics as a multipurpose tool for such problems and decided to use that as a basis to help attack this issue.
What it does
The wearable delivers a sharp tug to the user and tightens the bracelet and retracts when over a fixed speed limit measured by a sensor. We have demoed two modes here, one for a high speed threshold and another for a low speed threshold for the user to experience both a short and a long period of squeezes. These squeezes are meant to indicate that the user should ideally slow down a bit or a lot depending on the number 2 vs 4.
How we built it
We started with an Arduino board and spent a large portion of time figuring out how to get an instantaneous velocity component then we used this velocity to trigger our servo and create a squeeze.From there it was a matter of using the right length of thread and cardboard to mount and put it all together.
Challenges we ran into
The biggest challenge we ran into was the age old accelerometer integration error issue where we tried simply using numerical integration to find the instantaneous velocity in fixed steps of 10ms but we had no way of accounting for the drift and the compounding error from the velocity measurements of the previous cycle rendering our serial measurements a bit moot. We tried compensating by finding a gyroscope or relevant support to give a second basis for the data but we ended up pivoting to using the Iphone's inbuilt suite of sensors to get a linear acceleration which had the correction applied to finally do our integration and finish our mechanism.
Accomplishments that we're proud of
We learned to use the Arduino Cloud ecosystem and trigger a servo to sweep across a fixed axis. We used a 3d printer to create a custom barrel to power our winch mechanism holding the excess paper we had.
We made a simple callback setup to check both thresholds and we learned a lot about the fine differences between an accelerometer, gyroscope, and an IMU. We learned to interpret the differences in analog and digital pins and clarified the understandings we had of baud rates when serializing data to the UNO.
What we learned
The greatest lesson by far was that an insurmountable goal like designing a wearable can be made very doable by applying constraints and generalizing these constraints beyond their initial conditions. Ethan, Raymond, and Myself all found this experience to be quite enlightening on the prototyping process. We were constantly fluctuating between design and implementation as we rushed to finish our wearable's mechanism and the integration with the flashed UNO itself.
One change I would make though is that I would try to branch out a bit from the UNO ecosystem in the future and try to embrace more general and industry based solutions perhaps a PI might be a fun project for next time or even pursuing an even more ambitious project about one's posture and computer vision as well.
What's next for Souvik’s Speed Sensing Super Safety System
We plan on potentially adding in an LCD, a portable power supply, a few small sensors attached to the forearm to substitute for the Iphone's sensor and finally a way to log the data for future troubleshooting and fine tuning for user customization. We might even add a small animation and a few design elements to make it a bit nicer as well to fit the theme of Steel and Steam.
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