by Stephanie Gooch and Richard Mandel

The distinctive sound of the electric guitar ironically arises from the magnetic influence (or interference) of the pickup on the ferrous strings—what was an unfortunate side-effect of making the instrument audible to larger audiences has become an integral sound to popular music. Piezo pickups are sometimes used for sensing the vibrations on the bridge without changing the string motion, but this indirect transduction does not accurately represent the acoustic sound. LightWave Systems, Carpinteria, CA, offers “purity” to amplified instruments with optical pickups, which sense the actual string vibration without changing the tonal properties of the guitar. The system, which works equally well with strings of other alloys and composites, employs a proprietary transducer that uses an infrared emitter and an array of photodetectors for each string. The size and shape of each string’s shadow modulates a standing current passing through the photodetectors. This signal is conditioned and converted into either a single standard electric guitar output or an individual one for each string. As many musicians are hesitant to return to a purer sound, the company has entered the OEM market first with acoustic bass guitars, citing the genre as being more receptive to “new” ideas. Electroacoustic and electric guitars are slated to arrive in the coming months. Circle 152—LightWave Systems, or connect directly at www.rsleads.com/202df-152

Parker Hannifin Corporation has been exhibiting Bluetooth-enabled concepts at trade shows this past year, anticipating their introduction within the next several months. The company has also been exploring applications using IEEE 802.11b (also known as Wi-Fi), which offers networking speeds higher than Bluetooth but without Bluetooth’s size, cost and power advantages. Potential applications include climate and industrial controls, industrial automation, and other mobile systems and equipment. Sandy Harper, senior R&D project engineer for the company, observes, “Wireless technologies will enable machines to be programmed and actuated, and provide automatic status reporting to either a central controller, or an operator with a pocket PC or other wireless device, even a cell phone. The reduction of cables and connectors from the manufacturing floor,” she continues, “will, in turn, speed installation, reducing maintenance and troubleshooting. Even at $10 or more for a Bluetooth sensor, the cost savings to industrial users going wireless would be significant.” Taken at the 2001 Hannover Fair, the photo shows a “smart” cylinder next to a pneumatically controlled valve bank, in which 14 Bluetooth modules replaced 14 cables, 28 connectors and eight I/O modules. Circle 153—Parker Hannifin Corp, or connect directly at www.rsleads.com/202df-153