The tunable acoustic gradient index (TAG) lens is capable of producing rapidly tunable complex optical beams and patterns from a single source beam. The lens uses piezoelectric transducers to modify the density and refractive index within a fluid to generate lensing behavior. The type of beam that the lens generates depends on the electrical driving signal applied to the piezoelectric transduce...

This report describes a low cost indoor position sensing system utilising a combination of radio frequency and ultrasonics. Using a single rf transmitter and four ceiling mounted ultrasonic transmitters it provides coverage in a typical room in an area greater than 8m by 8m. As well as finding position within a room, it uses data encoded into the rf signal to determine the relevant web server f...