32C3: Vector Video Games

There are a few classic video games that rely on vector graphics and special monitors. Asteroids is incomplete if you’re not playing it in its original arcade format. The same goes with Tempest, Lunar Lander, and the 1983 Star Wars arcade game. Emulation of these games is possible, even with MAME, but the display – like every display you can buy today – is still rasterized. The solution to this problem is to create a vector display output for MAME that works in conjunction with adapter boards and DACs connected to a monitor.

For this year’s Chaos Computer Congress, that’s exactly what [Trammell Hudson] and [Adelle Lin] did. They’ve created an open source vector gaming system that connects MAME to XY monitors and oscilloscopes.

The build uses a custom board equipped with a Teensy 3.1 microcontroller and a 12-bit DAC to convert XY coordinates sent by MAME to vectors that can be displayed on any XY monitor. This, of course, requires a patch to MAME, which the maintainers rejected as being an, “unacceptably hacky way to achieve the intended result.” It does achieve the intended result, though: allowing dozens of vector games playable on whatever monitor supports vector graphics.

So far, [Trammell] and [Adelle] have gotten their system working on Vectrex consoles, analog oscilloscopes set to XY mode, and vectorscopes that litter every broadcast station and surplus shop. Check out [Trammell] and [Adelle]’s talk, and if you want to build the V.st vector display driver, the board is available from OSHPark.

Vector plotter with lasers

[Hubert] sent in his experiments using HDDs, CDROMs, speakers, and other components to make an XY laser plotter. Those carefully reading will note, its not all three to make one plotter, but rather three plotters each using a separate system. The setups have their advantages and disadvantages, and [Hubert] is sure to point them out; including circuit diagrams and pictures to help you on your own trials.

There is a little difficulty in reading English not so good, but considering we’ve never seen a single-laser vector plotter done before (spirographs come close, and no one wants to wait 85 seconds) it’s still very impressive.

[Thanks TJ]

Cheap XY table using hobby servos

[CarlS] wanted to build a low cost x y table for display on teletoyland.com. He realized that to keep cost low, he could use hobby servos instead of stepper motors. Exact precision wasn’t a big issue here, so the hobby servos would be perfectly acceptable.

Though Linear hobby servos are available, he decided that the cost was prohibitive.  He used normal hobby servos, but had to modify their internals to get the exact amount of travel necessary. Many people modify the hobby servos for continuous rotation, but this would cause a loss in the ability for exact positioning. Instead, he replaced the potentiometer that measures the position of the servo with a 10 turn potentiometer. This allowed him 10x the travel.

Continue reading “Cheap XY table using hobby servos”