 IntelliPen’s advanced digital positioning technology is based on the transmission of ultrasonic acoustic waves between two or more devices via a Transmitter and a Receiver.
The Transmitter, embedded in a device such as a pen or other wireless terminal sends constant acoustic signals to the Receiver that in turn, uses them to measure the distance and position of the device(s).
The Transmitter
The Transmitter sends a unique ”whistle” (an ultrasonic signal with specific time and spectrum characteristics assigned to each device) to the Receiver, constantly informing it of its position. The IntelliPen’s Receiver ”hears” the whistle and uses the sound to estimate with pinpoint accuracy the timeframe it takes the acoustic wave to travel from the Wireless Terminal to the Receiver, by calculating time-of-flight (TOF).
Time of Flight
Although analog acoustic TOF measurements have been used for many years in determining position, EPOS' innovative technology has taken the acoustic domain and transferred it to the digital domain. The digitization of acoustic media enables IntelliPen to support many devices simultaneously (very much like cellular phones). At the same time, other user experience-related positioning features were also greatly enhanced including: accuracy, power consumption and refresh rate. Each wireless terminal is equipped with one or more ultrasonic transducers that transform electric signals into acoustic waves.
The Receiver
Each IntelliPen Receiver is designed to “hear” up to 96 different wireless terminals, each ”whistling” its own individual signal, via two or more microphones embedded in the Receiver.
The number of transducers and microphones used depends on the application, as does the number of ”degrees of freedom” (coordinates and angles in space) required for the wireless terminal. For example, for the simplest wireless input device (i.e. mouse/pen), only two coordinates (X, Y) of the pen tip are needed, therefore, only one transducer is required in the wireless terminal and two receiver microphones will suffice.
Many transducers can be placed in one wireless terminal as many microphones can be added to the receiver.
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