| 摘要 |
A computer input device uses an ordinary sheet material such as a card, letter or envelope to select and point to a symbol. A remote portion of the sheet material covers adjacent light emitters and sensors which sense reflected light from the emitters. A single sensor is associated with multiple symbols and is associated with symbols in at least two specific groups of symbols. A processor is connected to a demultiplexer and a multiplexer, and the demultiplexer and multiplexer are connected to individual sensors. Biasing resistors are connected to individual sensors. The processor selects a pair of connectors from the demultiplexer and multiplexer, thus sampling a particular sensor. The output of that sensor is converted a digital signal, which is sent to the processor and stored in a random access memory. After sufficient sensors have been interrogated, the processor provides an output which is particularly related to the sensor or group of sensors which are covered by the pointer sheet, and which is specifically related to a symbol pointed to by the pointer sheet. In one embodiment, the processor output is displayed as a particular information.
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