Tiny MAME Cabinet Built From Raspberry Pi

November 26, 2012 by Brian Benchoff 17 Comments

It’s been a while since we’ve seen [Sprite_tm] pull a project from thin air, and we haven’t seen him do anything with a Raspberry Pi yet. All things must pass, and finally [Sprite] has unleashed his tiny, pocket-sized MAME machine to the world.

The build uses a Raspi for all the Linux-ey and MAME goodness, but [Sprite_tm] didn’t want to fiddle around with the HDMI or analog video output. Instead, he chose to use an SPI-controlled TFT display that is only 2.4 inches across. This isn’t a new hack for [Sprite] – he figured out how to connect this display over GPIO pins with a Carambola earlier this year.

To make his cabinet portable, [Sprite] opted for using old cell phone batteries with a cleverly designed charging circuit. When the power supply is connected to +5V, the batteries charge. When this power is removed, an ATtiny85 provides 5V of power to the Raspi and display.

No arcade cabinet is complete without a marquee of some sort, so [Sprite] used an extremely tiny 128×32 white OLED to display the logo of the game currently being played. Everything in the Raspi is set up to be completely seamless when switching between games, automatically configuring the controls and marquee for the currently selected game.

You can check out [Sprite]’s mini MAME booting straight into Bubble Bobble after the break along with some gameplay footage and finally switching it over to Nemesis. A very awesome build from an exceedingly awesome maker.

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Playing Led Zeppelin On A C64

November 14, 2012 by Brian Benchoff 24 Comments

[youtube=http://www.youtube.com/watch?v=Iikj5EfL770&w=470]

In the C64 demoscene there are a ton of awesome software hacks that push the Commodore 64, the 1MHz 6510-based computer from 1982, to its limits. Most of these C64 demos are very much limited by the hardware inside the C64, but the demoscene is always coming up with new ways of pushing the envelope. [No Quarter] just sent in one of these software hacks that propel the capabilities of the C64 into the realm of absurdity by playing full length songs directly from the floppy drive.

Playing a song on the C64 begins with an Amiga and a Perfect Sound digitizer to convert the digital audio file into a 4-bit sample. Once this sample is transferred over to the C64 where it was manually timed so streaming it off a 1581 disk drive would result in the song playing at the correct pitch. It’s an amazing work of optimization; the audio data is streamed off the disk just as fast as it’s played from memory, an amazing data throughput rate for the ‘ol C64

After the break you can see [No Quarter] playing Led Zeppelin, Bon Jovi, Shania Twain, and Extreme. A very, very cool project and with the addition of a C64 hard drive makes it possible to have a media player for the C64.
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Storing 32 Bits Of Data In A Piece Of Glass

November 9, 2012 by Brian Benchoff 36 Comments

After finding an old piezoelectric delay line in an old TV, [Mike] decided to figure out how it works and in the process stored his name in sound waves reflecting inside a piece of glass

[Mike] was intrigued by these old-fashioned delay lines after watching [Dave] from EEVblog’s teardown of an circa 1985 camcorder. [Dave] found a piezoelectric delay line in his camcorder – a device that is able to store digital data by sending a sound wave into a glass plate, letting the sound wave bounce through the plate. and picking up the sound on the other end. It’s actually not too dissimilar to a mercury delay line used in the earliest computers.

After sending a pulse through his piezoelectric delay line, [Mike] picked up an echo almost exactly 64 microseconds later. After hooking up a simple circuit constructed out of a 74-series chip, [Mike] found he could ‘loop’ the delay line and keep a pulse going for up to 3 milliseconds.

Three milliseconds isn’t much, but by injecting serial data into the delay line, [Mike] was able to spell out his name in binary, as seen above. It’s just 32 bits stored for a fraction of a second, making it a very volatile, low-capacity memory, but functionally equivalent to the old mercury delay lines of yore.

It’s certainly not what [Mike] or [Dave]’s delay line was designed to do; these video delay lines were used to hold the previous line of video for a form of error correction. Outside [Mike]’s workbench and a few museums, though, you won’t see a delay line used as a form of computer memory. A very cool build and an awesome history lesson, and we thank [Mike] for that.

Reliving 1977’s Cutting-edge Computer With The Pocket Mini Computer

November 6, 2012 by Brian Benchoff 19 Comments

Classic computers are just up [Jeff]’s alley, so when he looked for a new project for his Pocket Mini Computer, he looked at one of the earliest microcomputers available: the COSMAC VIP, a 1.76 MHz beast from 1977.

The COSMAC VIP was a single-board educational computer released by RCA in 1977. Priced at just a hair under $300, the COSMAC was much more affordable than infamous $1300 ‘fruit’ computer also released that year. To get young programmers up and running quickly, the COSMAC came bundled with the CHIP-8 programming language, making it very easy to generate graphics on-screen for all the eventual PONG and Breakout clones.

[Jeff]’s COSMAC VIP runs on a Pocket Mini Computer, a very cool Parallax Propeller-powered board we’ve seen before emulate other retro computers including the venerable Commodore SID synthesizer chip.

Because the COSMAC’s user interface was the very, very old-school 4×4 hexadecimal keypad, [Jeff] found it necessary to emulate this retro feature by soldering his own 4×4 keypad. After soldering 16 buttons into 8 columns and rows, [Jeff] connected this keyboard to a PFC8574a I2C I/O expander and connected this chip to the I2C bus on the Pocket Mini Computer.

The result is an emulated COSMAC VIP that’s just begging for an ‘introduction to microprocessors’ class or just a round of Tetris, Tic-tac-toe, Lunar Lander, or one of the several Breakout clones available for this very cool computer. A pretty awesome build, even if it is from the dawn of the computer age.

Myst Book Plays Myst, Doesn’t Transport You To Other Ages

October 30, 2012 by Brian Benchoff 58 Comments

We shouldn’t have to remind you, but back in the early 90s one of the most popular computer games was Myst. Despite having the gameplay of a PowerPoint presentation, Myst went on to become one of the best-selling video games of all time and the killer app that made a CD-ROM drive a necessity rather than a luxury. [riumplus] loves Myst, and after 6 long years he’s finally completed his homage to his favorite game. It’s a replica of the in-game Myst book that is able to play every game in the Myst-iverse.

The build started off by searching for the same book used as a model for the book object in Myst. It’s a 135-year-old edition of Harper’s New Monthly Magazine, Volume LIV, Issue 312 from 1877. In keeping with the in-game assets, [riumplus] made dies for the spine and cover, embossed the word ‘MYST’ on the book, and filled these letters with 24-carat gold paint.

Inside the newly hollowed-out book [rium] added a very small x86 motherboard running Windows XP on a 32 Gig Compact Flash card. This tiny computer is able to run every Myst game ever made on a very nice touchscreen display.

It’s a work of art in our humble opinion, and a fitting tribute to the last great hurrah of the adventure game genre. After the break you can see [rium] interacting with his book, or just check out the build pics on [rium]’s Google+ page.

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Hackaday Retro Edition: The Macintosh SE/30

October 28, 2012 by Brian Benchoff 45 Comments

In 1988, Apple introduced the Macintosh IIx, an upgrade of the Mac II that included a Motorola 68030 CPU. The IIcx – a compact version of the IIx, also with a 68030 – was introduced in 1989. That same year, product designers at Apple created a more powerful version of the all-in-one Macintosh SE using the same CPU found in the IIx and IIcx. Unfortunately, the naming convention didn’t hold but the Macintosh SE/30 is still the greatest computer Apple will ever build.

Earlier this month, [Greg] sent in a submission for our retro edition successes. A huge mac fan, [Greg] connected his Powerbook Duo to an Ethernet adapter and loaded up our retro edition. [Greg] is back again, this time with an SE/30.

In the three pictures [Greg] sent us (in the gallery after the break), you can see his extremely clean SE/30 booting into System 7 and loading up our retro site. In the third picture, you can see [Greg] playing Bolo, one of the first network-enabled games ever made, and still a very fun waste of time today.

If you’re wondering what makes the SE/30 so great, consider this: the SE/30 is able to address up to 128 MB of RAM. Keep in mind this computer is from an era when one or two Megabytes of RAM would be more than enough to get just about any job done. The SE/30 also made a fabulous server. Even today it would be a capable home media server if it weren’t for its relatively slow networking capabilities and 2 Gigabyte file size (not volume size) limit.

[Greg] has a very cool machine on his hands here, and we’re pleased as punch his SE/30 could make its way over to our retro site.

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Making A Phono Preamp For A First Electronics Project

October 27, 2012 by Brian Benchoff 34 Comments

Nearly everyone’s first electronic project is something that blinks a LED. There are a million ways to go about this ‘Hello World’ project of electronic design; 555 timers, microcontrollers, or maybe even discrete components if you’re really cool. When [miceuz] was asked by a friend to help with his first electronic project he eschewed the usual blinking LED project and taught him how to build something he actually needed: a phono preamp for an old turntable.

Back in the day when vinyl was king, albums needed to be mastered to play on a record player. The mastering process cuts some of the bass and increases the treble. When the record is played, this process needs to be reversed. It’s a preamp that does this job by attenuating the high frequency sounds and boosting the thumping bass.

[miceuz] found a nice DIY RIAA preamp project and found a nice little op amp somewhere in his parts bin. After laying out the circuit, [miceuz] etched a few boards and taught his friend how to solder SMD components.

Of course the project didn’t work the first time around, but after poking around with a meter and checking out the old turntable, the preamp came to life with the clang of chords from an old record. If you’d like to build your own, you can get the files from [miceuz]’s git.