Smaller Paddles = Bigger Fun

[Kaizen]

The Kelso Mod

 

 

 

Original Paddle Size:

 

 

Modded Paddle Size:

 

 

I saw this mod a while ago and decided to knock it up and see if it works.

Most of the info below has been copied from here... https://imgur.com/gallery/A5piX

 

In season 1 Ep22 of That 70's Show, Kelso mods a Pong to make the paddles smaller.

If you play Pong for a while it can get a little boring especially if there are two equally skilled, good players.

This mod adds another level to the difficulty.

 

Game play video:

 

http://www.youtube.com/watch?v=NjSE7dnwyF8

 

Video explaining the inspiration:

 

 

 

Paddle 1 Control - Original Schematics

 

 

 

Paddle 1 Control - Modded Schematics

 

 

 

Getting smaller paddles is fairly simple (if you understand digital electronics). In normal operation the 555 timer is triggered by vertical blanking, delays for a time set by the players control, then triggers the 74LS93 4-bit counter. The counter increments every horizontal sweep, from 0 to 15 (total 16); from 0 through 14 the NAND output is 1 which means the paddle is drawn on screen. On count 15 (binary 1111) the NAND output goes to zero, stopping the counter and the drawing of the paddle, therefore the paddles are 15 vertical pixels long. Signals B, C and D are used to calculate where on the paddle the ball collided, which sets the return velocity. This process is re-triggered every 1/60th of a second by the vertical blanking.

 

To get smaller paddles:

Signals B, C and D now use the lower 3 bits (weighted 1-2-4) of the counter instead of the upper 3 bits (weighted 2-4-8). The NAND stops the counting at 7 (binary 111) instead of 15. Thus the paddles are 7 vertical pixels long. In theory, the paddles could be set to any number of pixels from 1 to 15.

 

Here's the mod itself..

 

Edited May 9, 2021 by Kaizen

[Kaizen]

I've just drawn up a riser board for The Kelso Mod...

 

 

 

Here's a link to the Gerber file if anyone wants to get a PCB fabricated.

 

https://drive.google.com/file/d/1Ax3GUJvV0oZ0-LK-ijmMgW057kguPrk6/view?usp=sharing

 

It's just a matter of socketing the two 7493 IC's at A8/B8 on the Pong PCB, placing the chips from A8/B8 onto the riser board at A8A/B8A and inserting the riser board into the sockets.

[jbtech]

That looks soooo much neater and easier than the previous version, think you could get enough orders for the complete mod to produce a batch!

 

To get smaller paddles:

Signals B, C and D now use the lower 3 bits (weighted 1-2-4) of the counter instead of the upper 3 bits (weighted 2-4-8). The NAND stops the counting at 7 (binary 111) instead of 15. Thus the paddles are 7 vertical pixels long. In theory, the paddles could be set to any number of pixels from 1 to 15.

 

Shifting the bits down 1 level (and resetting at 7) is the smallest you could go and still obtain the correct bounce angles, I think. Regards, John

[Kaizen]

Yeah, definitely a big improvement on the previous method and yeah, you wouldn't want to go any smaller.

I'll do a run of 10-20 boards next time I put an order in with JLCPCB, they cost bugger all to make if thrown in with another order.

I may modify the design to use a dipswitch or toggle switch to turn the mod on/off.