Credit: Mark Stone/University of Washington
Engineers at the University of Washington created a 3-D printed prototype of a device that can store information, such as how many times someone used an insulin pen, by rolling up a spring inside a ratchet that can only move in one direction (shown here). When the user releases the ratchet, the spring unwinds and moves a gear that triggers a switch to contact an antenna. Each contact is counted to determine how many times a person used the device.