Consideration of an Image Sending System of Electronic Blackboard

Abstract

The change of electronic property produced by the writing pressure was utilized in designing a basic device for an electronic blackboard system.
The irregular time interval output signal corresponding to the change of resistance value of a conductive sheet is stored in RAM as address information. The signal rearranged by the microcomputer is possible to transmit as a regular pulse train on the ordinary telephon lines. The frequency bandwidth is reduced as pressure points are successively monitored as moving information by line and local scanning. Further more, the image is successfully reproduced on CRT by the method that detects the maximum pressure points.