Method and apparatus for downloading information from a controllable light source to a portable information device
US5488571A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 22, 1993 |
| Grant date | Jan 30, 1996 |
| Priority date | — |
| Expiry date | Nov 22, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F15/0225
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A system for transferring data from a CRT (cathode ray tube) video display monitor on a personal computer to a portable information device such as a multifunction electronic wristwatch. The CRT video display has a video signal generator providing raster scanning of the screen and a program for formatting the binary coded data into blocks of serial data bits, with start bit and stop bit. The blocks of data are supplied to the video signal generator in synchronism with raster scanning of the screen so as to provide an integral number of one or more blocks of data for each vertical frame, and modulated to vary the brightness of the screen and provide light pulses corresponding to presence or absence of binary coded transmitter pulses. The portable information device is manipulated within line of sight of the CRT screen and has a photosensor to detect light pulses when the photosensor is directed toward the screen. Signals from the photosensor are amplified and filtered to remove ambient light source flicker and extraneous spurious light signals and to convert the receiver pulses to binary coded data blocks varying between high and low logic levels at a preselected pulse repetition rat…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.