Acoustics researchers at the Georgia Institute of Technology (www.me.gatech.edu) have developed a piezoceramic actuator to eliminate brake squeals that occur when a vehicle slows down and the brake pads contact the rotor, setting up a vibration that manifests itself as a high-pitched noise. Mounted inside the brake piston, the actuator can suppress the vibration by applying bursts of a 20-kHz dithering frequency—above the human hearing range—to the backing plate of the inside brake pad. An open-loop control system that is connected to the brake-light switch, the actuator does not need any detector or logic system to determine the proper control frequency.
A make-your-own Star Wars Sith Lightsaber hilt is heftier and better-looking than most others out there, according to its maker, Sean Charlesworth. You can 3D print it from free source files, and there's even a hardware kit available -- not free -- so you can build one just in time for Halloween.
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