Abstract: A signal controller for a musical instrument such as a guitar includes a liquid-filled tilt-sensor that has means to cause a variation in electrical resistance that is exploited by control circuitry to vary one or more qualities of the signal of the musical instrument. Such a signal may be a volume control, a tone control, a balance control and/or an effects control.

Abstract: Systems and methods consistent with principles of the present invention allow contactless measuring of various kinds of electrical activity within an integrated circuit. The invention can be used for high-bandwidth, at speed testing of various devices on a wafer during the various stages of device processing, or on packaged parts at the end of the manufacturing cycle. Power is applied to the test circuit using conventional mechanical probes or other means, such as CW laser light applied to a photoreceiver provided on the test circuit. The electrical test signal is introduced into the test circuit by stimulating the circuit using a contactless method, such as by directing the output of one or more modelocked lasers onto high-speed receivers on the circuit, or by using a high-speed pulsed diode laser.