As any serious bicycle commuter will tell you, it's important to let drivers know what you're doing by signaling your intention to turn. Needless to say, the more visible your hand signals are, the safer you should be. That's why a group of doctoral students at Switzerland's EPFL research institute created the Intelligent Blinker. It's a wrist bracelet that automatically starts flashing when the wearer raises their arm to signal.
The device (which would presumably be worn as a set of two) contains an accelerometer and a magnetometer, to detect changes in the orientation of the bracelet. When the arm moves out laterally, those sensors trigger a set of integrated LEDs to begin blinking. Depending on how enthusiastic of a signaler they are, the user can adjust the Intelligent Blinker to kick in at more or less of an angle, as desired.
The bracelet can be charged by USB, although it also has a built-in photovoltaic panel. In its present prototype form, its circuit board is too large for practical use, although the students plan on reducing the size of the device to that of a wrist watch. They also hope to reduce its energy consumption, and add additional functions via more sensors.
Not surprisingly, other people have already taken their own shots at flashing hand signals for cyclists. The Safe Turn bracelet automatically lights up when signals are made, although it utilizes an internal tilt switch instead of an accelerometer or magnetometer. We also recently heard about the LED-arrow-equipped Zackees cycling gloves, which are manually activated (as are the Doppelganger gloves).
A device more technologically similar to the Intelligent Blinker, the Useeme Bicycle Turn Signals bracelet, recently failed to reach its funding goal on Indiegogo.