That mysterious buzz you hear when you are driving your car can be an annoyance, but unexpected vibrations are often symptoms of deeper technical problems in machines such as aircraft engines or power transformers. That’s why physicist Philip Melese of SRI International in Menlo Park, CA, has developed a novel instrument that helps people pinpoint a wayward vibration by allowing them to “see” sound. The device contains optical sensors that detect the minuscule fluctuations in intensity that arise when light reflects off a vibrating surface. The sensors send their readings to a computer, which generates an acoustic map showing the vibration levels in each section of the object.
SRI has packaged these sensors into a “vibration camcorder,” which when pointed at a visible object will measure its vibrations. This beats existing measurement methods that require the tester to attach sensors directly onto the test object or to set up intricate laser systems. Several companies have expressed interest in the technology, which SRI hopes to see commercialized within two years.