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
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.