Abstract: A system for generating digital ink from triangulation data of a stylus comprises an electromagnetic radiation source capable to emit electromagnetic pulses; a first and a second ultrasound detector separated from each other by a known distance; a timer coupled to the radiation source, the first detector, and the second detector, and capable to measure a first elapsed time between emission of an electromagnetic pulse from the radiation source and detection of an ultrasound wave at the first detector, and further capable to measure a second elapsed time between emission of the electromagnetic pulse from the radiation source and detection of an ultrasound wave at the second detector; and a triangulation engine coupled to the timer and the radiation source, the engine capable to instruct the source to emit a plurality of radiation pulses, to triangulate the position of an ultrasound transponder over time based on the first elapsed time, the second elapsed time and the known distance between detectors, and to gen