Sun Spot: portable UV detection
Introduction to Physical Computing project and part of CMU's IDeATe Program
My group constructed a wearable device that can attach to a backpack or bag and notifies the user when they have been exposed to too much UV radiation. The audience for this project includes people who spend a significant amount of time outdoors and are concerned about preventing skin cancer and other UV radiation exposure related diseases.
The notification system has two responses: it quickly buzzes once on every hour except the fourth hour where it would continue to buzz until the user cuts off their UV exposure by going inside or sitting in a shaded area. Once the threshold drops, the buzz will end and the loop will start over again. This timing was chosen because after an hour of UV exposure erythema, or sunburn, of the skin begins, and after four hours the damage to skin cells peaks to dangerous levels.
The device consists of a UV sensor, pulse motor, and a Teensy 3.1 microcontroller. All of the elements were soldered to a protoboard and two pairs of coin batteries were wired in parallel to give the unit 6V of Power. The sensor takes a reading once every second, and calculates an average of the last minute's worth of values. The housing allows for the sensor to receive light and allows for battery changes while keeping the device contained and protected.