Touchscreens are everywhere. They're easy to use, intuitive, and natural. However, with every touch screen comes a glass panel that serves as an interface between the analog and digital worlds. With smartphone pricing surging to over $1000, it has become a very expensive accident to drop your phone. Until now, that is. We're building a smarter phone case that senses when your phone is being dropped and deploys an emergency contraption to reduce shock and protect your phone and its screen.
Promo Video: https://youtu.be/s6-kcJlrIfg
The billions of dollars spent on replacing phone screens every year and the extraordinary, ridiculous amounts of caution that we have to live with to protect our beloved screens from cracking.
What it does
Our project is an intelligent smartphone case that can automatically detect when a device is falling and trigger a mechanism to protect its screen.
How I built it
The initial idea was to use an accelerometer to detect when the phone is falling, but this would lead to a lot of unnecessary false actives as well as data that is a lot harder to read and make sense of. To simplify our device, we used a pressure sensor and a proximity sensor, and if neither one of them detected a high, we realised the phone would be in free fall.
We used the pressure sensor and proximity sensor as inputs to an Arduino and coded it so that, when pressure is low (the phone is not on a desk or in a hand) AND proximity is high (phone is not in a pocket), an LED lights up. An if statement with the write values was sufficient for this.
For the solenoid, we tried using the Arduino's digital out pins to digitally turn it on and off, but they didn't even have enough current for a single solenoid. After much trial and error with Op-Amps, Inverters, and Capacitors, we built a circuit that uses a MOSFET and a Capacitor in series to digitally deliver the voltage and current needed to drive the solenoid from the triple output. This also meant our device would be wired and require a lot of soldering. Using the MOSFET-Capacitor circuit, we could deliver this amount of power without losing much across components. After some taping, the product finally worked.
Challenges I ran into
The main challenges we faced in this project were initially software based. We had to find a way to efficiently detect the fall, as well as correctly read values from the two sensors, which would go on to malfunction frequently throughout the project. Secondly, figuring out a mechanical countermeasure (the solenoids) took a while and powering it so that it could turn on and off digitally was a significant challenge that involved scouring data sheets and sample circuits.
Accomplishments that I'm proud of
Making the phone case actually work, even though it's nowhere near finished was incredibly satisfying and it required a lot of trial and error, especially with the activation of the solenoids
What I learned
This obviously taught us a lot of hardware debugging, as well as how to read datasheets. We also learned soldering really well because of how many wires we had to extend in length.
What's next for justinCASE
This product can be improved significantly given the right resources and we believe it can reach the mass market one day. With the right expertise, the proximity sensor built into the phone can be used rather than an external component. This would require an app but make the look as well as the efficiency much better. The case itself would be a battery powered collection of pressure sensors as well as solenoids that stuck out to protect the screen. Powering the case so that it's a rechargeable device rather than something that requires to be constantly plugged in would make the product a lot more usable as well as more aesthetically pleasing. All of these challenges can be overcome using smaller components and sophisticated manufacturing.