Patent ID: 8599155

Claim:
A method for sensing a touch to a substrate and determining a location thereof, said method comprising the steps of: providing a serpentine transmission line fabricated on a substrate comprising a plurality of touch locations having a first and second end; unterminating a second end of the serpentine transmission line; sending a first pulse to the first end of the serpentine transmission line; charging a timing capacitor with a constant current source until a first touch return pulse is received at the first end of the serpentine transmission line; measuring a first voltage on the timing capacitor; converting the measured first voltage to a first location on the substrate; unterminating the first end of the serpentine transmission line; sending a second pulse to the second end of the serpentine transmission line; charging the timing capacitor with the constant current source until a second touch return pulse is received at the second end of the serpentine transmission line; measuring a second voltage on the timing capacitor; and converting the measured second voltage to a second location on the substrate.