Arcade Games – PONG

PONG in a picture frame

Atari’s original PONG arcade game has an interesting design: No microprocessor or program; the whole game logic and signal generation are hard-wired from sixty-some TTL chips. So, when I got my hands on an original 1972 PONG circuit board, I wanted to build a playable cabinet around it, but also display the board with its surprisingly low-integration components.

I decided to take my half-scale Asteroids idea a step further, and give center stage to the circuit board in a cabinet styled like a picture frame. The shallow depth of the frame (6 cm, a good 2") means that there is no room for a period-correct cathode ray tube; an 8" TFT is used instead. But I added a homebrew, FPGA-based video upscaler to simulate scan lines, horizontal blur and some phosphor afterglow, which makes the image look “right” to my eyes.

While this project is complete and has turned out nicely, this web page is preliminary. Just a few pictures for now, to give you an idea, and some relevant links and project files.

Gallery

The finished PONG cabinet. Wall-mounted, with mains power supplied via a wall outlet behind the frame. The cabinet is 74 cm tall, 29 cm wide, and 6 cm deep.

PONG front panel — The complete front panel and circuit board are covered by a pane of slightly tinted perspex. The yellow front and the 'aluminum' panel are simply laser-printed. The two paddle knobs and a coin button are real, of course.

Screen closeup — An 8" TFT flat screen is used, but the FPGA video upscaler adds scan lines, phosphor afterglow and a bit of horizontal blur, to get close to the looks of the original cathode ray tube.

Interface board on the PONG PCB's edge connector — A small interface board sits directly on the PONG board's edge connector. It amplifies the sound, splits the video output into a sync and a brightness signal for the upscaler, and feeds a regulated +5V supply to the PONG board. PONG's on-board voltage regulator is bypassed, to improve reliability and reduce the heat load in the cabinet.

PONG with half-open front — The whole front slides up to give access to the innards, for installation and service. The FPGA video upscaler and 5V power supply sit below the screen. The speaker and controls are attached to the front panel. They get connected via a Sub-D jack in the upper left that clicks into place when the front is lowered all the way.

PONG internal components — The TFT screen is set back and tilted backwards a bit, reminiscent of the original PONG cabinet. The opening on top provides ventilation and an outlet for the speaker sound. To allow air circulation, the whole frame sits away from the wall on 1 cm spacers, and there is another ventilation opening at the bottom of the back panel.

PONG front panel from behind — The backside of the front panel. The little speaker is mounted here, behind a baffle which helps to get a bit of low end. The baffle and the trapezoidal screen bezel were cut from 1.5 mm cardboard. The Sub-D jack which connects the paddles, coin button, and speaker via its counterpart in the frame is visible in the upper right.

Files and Links

PONG information

PONG Story, a website dedicated to PONG, maintained by David Winter.
An in-depth circuit analysis of the original PONG arcade board, by Hugo Holden.
Full schematics of the original PONG arcade board.
One often reads that Atari did not patent PONG, and was hence confronted with many bootlegged versions of the game. In fact, they did file a patent application in November 1972. US patent 3,793,483 was granted in early 1974 – relatively quickly. Still too late to deter the pirates, or was the financial problem just not big enough to justify the effort of enforcing the patent?

My project files

Eagle schematic and board layout for the interface PCB and the FPGA piggy-back board.
Front panel design in Powerpoint format.
Several fonts are used in the front panel. I won’t provide download links here, since they change; but most fonts should be available for free somewhere. The PONG logo is “Brandish”, the instructions on the aluminum panel are “Eurostile”. The Player 1 and 2 designations are “Twentieth Century Condensed” – but strangely non-condensed for the actual digits 1 and 2. Finally, the old Atari logo is set in “Busorama” or “ITC Busorama”. That font includes the two mirrored versions of the ‘A’, as the upper and lowercase letter.
Routing profile for a frame made of 10 mm * 60 mm slats of mahogany. Hand-drawings, readable with some goodwill…

Key components

Numato Mimas, a small and low-cost Spartan 6 FPGA board.
TFT screen at Pollin, a German distributor of odd lots and Asian imports. May also be available via AliExpress; the model number for the screen/controller ensemble is given as JD70M6M- HL080IA-01E C35-HX/M, and the screen alone HL080IA-01E C35-HX/M.