It's the stuff of rock 'n' roll fantasy: a ring that gives its wearer the power to morph the sound of an electric guitar at will. Thanks to the pairing of an automotive airbag accelerometer with a customized version of a popular audio processor, a technology called Hot Hand claims to make that scenario possible. Devised by Analog Devices Inc. spin-off Source Audio LLC (www.sourceaudio.net), Hot Hand puts an ADI accelerometer chip in a ring that guitarists place on a finger of their picking hand. The movements of the ring are tracked by feeding the wired control signals into a box that houses an ADI-customized SigmaDSP--a 56-bit audio processor with 24-bit A/D and D/A converters and a 100-decibel dynamic range. Two foot pedals control on/off and cycling through user-defined presets. Source Audio was founded by two former ADI employees who convinced their former employer to create a customized version of its SigmaDSP for a system-on-chip called the Sound Audio 601 (SA601), to complement the low-power version of an ADI accelerometer chip (the iMEMS ADXL320). The co-founders then recruited former Kurzweil Music Systems Inc. chief scientist to craft the effects. Source Audio's first Hot Hand version applies the SigmaDSP-iMEMS combo to achieve wah-wah and volume effects. Other guitar effects are slated to follow soon.