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Diversions



The “Betagraph” was a moving message sign based on a two-dimensional array of LEDs. These LEDs were arranged, in the normal fashion, in a rectangular pattern consisting of many columns with, say, seven LEDs in each column.

What distinguished the “Betagraph” from other such signs (of which their weren't that many of, at the time - 1977, due to the cost of the technology) was that only one in every seven columns of LEDs was actually physically present. That is, the message was clocked across the sign using shift registers, as you might imagine, but there were seven shift register stages between each column of LEDs.

When you looked at the sign, initially all you would notice would be randomly flashing LEDs. However, if you allowed your eyes to move with the message, the LEDs would then paint the full message across your retina.

I don't believe that the concept ever saw the light of day, but it was an interesting idea.

The company involved, “Random Electronics”, was formed by a group of three punters who had shared in a large win at the horses. They paid for the rights to the concept from a professor in Western Australia.

Below is running a JavaScript / SVG2 simulation of the Betagraph.

A crude character-based demonstration of this function is also available for you to run or download the executable or to download the zip file that includes the Betagraph demonstration (111.3kB), then extract and run “betagrap.exe”. This is a Microsoft Windows Console application.

You would normally run this demonstration from an MS-DOS window, by typing in “betagrap” followed by the text that you wish to display, in double quotes. For example, you might type:

betagrap “Hello World”

The effect is a little better with a slightly longer message, with trailing spaces so that the start of the message is more obvious as it comes around each time, so try:

betagrap “Goodbye, cruel world ... ”

On the other hand, if all you want to do is to double-click on it, then, after it has advised you of how it expects to be used, it will allow you to enter the text to be displayed. Just type the text that you want on the console, then press [ENTER].

The other diversion included in this ZIP file is the “ Pentomino” program.