Pocket Police

This was part of my high school senior design project. We were given a budget of about $60, and tasked to solve a problem of our choosing. After spending some time brainstorming and selecting a problem, we decided to create a device to prevent pickpocketing.  

We went through about 6 -7 iterations of this product before settling on a final design. It is a completely analog system, in that there is a trigger arm that is depressed while the device is in the pocket. While the alarm is armed, it will be silent as long as the trigger arm is depressed (in pocket). If the device is removed, the trigger arm swings out and trips the alarm. As you can hear in the video, the alarm sound is a custom tailored cocktail of frequencies that was designed to pierce through crowds/white noise. Furthermore, now that everyone carries a phone and wallet, I developed a unique mounting system that allows the user to buy one device, and attach it to their phone or wallet. This also allows for future expansion of the product and its' capabilities later on.

This device is powered by a 55 mAh rechargeable lithium ion battery, and is controlled by a ATTINY85 Microprocessor (for the sound). If we were to develop this into market, I'd likely call for a full redesign, to slim it down, and switch out the analog trigger arm for a digital proximity sensor. However, this was an awesome learning experience at that age! If you want some more info, please send me an email!