Make-It-Yourself projects
Pongtronics sound & scoring (Popular Electronics, May 1976)

The May 1976 issue of Popular Electronics features add-ons for the Pongtronics article published in the April 1976 issue. It alllows adding sound effects and on-screen scoring. Digital on-screen scoring would not have been possible at an affordable price considering the number of additional chips required. Early game systems built with discrete components could use two main on-screen scoring techniques. The cheaper one (used in most cases) consists in displaying two squares (one per player) located on the top or the bottom of the screen. When a player marks a point, his square shifts on the right. An alternative design, as explained in this article, replaces the two squares by two expanding lines.
The second method is digital on-screen scoring. In the begning, this was only possible using a number of logic gates which combined the various signals generated by horizontal and vertical counters, a totally different technology than the one used in this article. Not only this technique would have been quite expensive, but it would have never been usable with Pongtronics which is based on a pulse design. An alternate method consists in using a small ROM containing the data of the digits to display, but this would also require the vertical/horizontal counters design. Texas Instruments designed a digital on-screeen scoring chip for the Magnavox Odyssey 400, but the chip was only used in this system.

Click the pictures below to read the article. You can also visit this page which contains interesting explanations and improvements for the original Pongtronics design.


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