Adding Digital Game Indicators To A Neo Geo Arcade Cabinet

January 19, 2012 by Mike Nathan 14 Comments

neogeo

[George] is a Neo Geo aficionado, and among his collection of paraphernalia, he has a MVS-Mini game console. His mini “Multi Video System” is a 2-slot model, meaning that it can hold two game cartridges at a time, which are indicated by plastic cards inserted in the cabinet’s face plate. Instead of swapping those cards out each time he changed cartridges, he thought it would be far cooler to install digital displays instead.

He scoured just about every retail store he could before finding a handful of small 5” digital picture frames that looked to fit the bill. After some careful cabinet modifications he had them wired up and ready for display. The frames don’t hold a ton of pictures, but they do support the use of SD cards. [George] says that he’ll likely just buy a ton of small SD cards, swapping them out whenever he changes games, though over time that might become as tedious as swapping out the plastic cards.

We would love to see [George] take his new digital display up a level, so be sure to share your ideas in the comments. Perhaps we can persuade him to automate things a bit.

Wii Nunchuck On An 80s Computer

January 16, 2012 by Brian Benchoff 3 Comments

For a computer that debuted in the early 80s the MSX was a very respectable machine. Of course these were the days that superimposing graphics over a video was an amazing feat, but [Danjovic] and [Igor] are still having fun with their boxen. They designed a software interface for the Wii Nunchuck (translation) on their trusty MSX computer.

The plug coming out the back of a standard Wiimote is just a simple I2C bus. Many things can be done with this port from plugging in ancient controllers to controlling robots. [Danjovic] and [Igor] managed to write a routine in Basic that converts the I2C data coming out of the Nunchuck to data the MSX can understand without any modification of the hardware whatsoever.

All the guys needed to plug the Nunchuck into the MSX was a voltage divider and a few pull-up resistors between the computer and controller. They got data from both buttons, the joystick and the accelerometer in the Nunchuck and made a small program to display some sprites on the screen to demonstrate this. Check that out after the break.

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The TIM-8 Is The Smallest 8-bit Relay Computer Ever

January 16, 2012 by Brian Benchoff 20 Comments

Who wouldn’t want to build a computer out of relays? We do, but we’ve got too many projects on our plate already. It looks like [rory] has his priorities in order because his build is one of the most amazing we’ve ever seen.

We’ve seen [Harry Porter]’s amazing relay computer and we’re familiar with [Konrad Zuse]’s WWII era endeavours. Relay computers aren’t exactly uncommon, but [rory] built the TIM-8, that may be the smallest 8-bit relay computer ever. The total relay count in the TIM-8 is 152 compared to [Harry Porter]’s 415 relays. This isn’t a fair comparison because [Harry]’s uses 4-pole relays, while the TIM-8 uses 1-pole relays, making the [rory]’s project 8 times smaller than [Harry]’s.

There are a couple of neat features that makes the TIM-8 really exceptional. Programs for the TIM-8 are written in a text editor on [rory]’s desktop, then compiled and printed onto receipt paper. The TIM-8 has a few phototransistors to read the bands of white and black printed on the paper. [rory] has come a long way from a three bit adder made with relays and light bulbs.

Check out a ton of videos after the break. There’s a few demos of programs running off of receipt tape, calculating the Fibonacci sequence, and playing ‘Mary Had a Little Lamb’ on the relay sound card. Thanks to [J. Peterson] for sending this one in.

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Universal Commodore 64 Cartridge Speeds Up Demo Production

January 11, 2012 by Brian Benchoff 13 Comments

As a life long lover of his venerable Commodore 64, [Frank] was looking for a way to speed up the development time when writing C64 demos. His solution is a universal C64 cartridge that will connect to a PC over a USB port.

The board is powered by a CLPD and a microcontroller loaded with code from [Frank]’s previous C64 USB controller adapter. A 16 Mbit flash chip is able to store 31 classic games like Pitfall, Dig Dug, and Lode Runner.

On his Google+ announcement, [Frank] says this is a very early prototype. He plans on reducing the board size to fit inside a standard C64 cartridge, and the firmware for the micro and CLPD aren’t finished yet. That being said, [Frank] does have a board that does what he wants it to do: extremely rapid C64 development.

Check out [Frank]’s demo after the break of him compiling and re-uploading a simple demo to his cherished computer in just a few seconds. That’s a lot faster than it would take with a 1541 Ultimate or other SD card reader.

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Help [Chris] Boot His Cray-1 Supercomputer

January 10, 2012 by Brian Benchoff 72 Comments

[Chris Fenton] needs your help. After constructing a 1/10th scale, cycle accurate Cray-1 supercomputer and finding a disk with Cray software on it, he’s ready to start loading the OS. There’s a small problem, though: no one knows how to boot the thing.

[Chris] posted a disk image for a Cray-1/X-MP with the help of the people at archive.org. Now he needs your help – if you think you can reverse engineer the file system, [Chris] will pay handsomely with a miniature model of a Cray printed on his MakerBot. In any case, it seems like a fun challenge.

From our quick glance at the disk image with a HEX editor, it looks like [Chris] has something special on his hands. We see a few references to “Cray memory and registers,” as well as “IOP-0 Kernel, Version 4.2.2” in the header along with a few dates referencing July of 1989. This is consistent with the history of the source disk pack. If you think you’ve got what it takes to reverse engineer the file system of a Cray-1, this is your chance.

Using 555 Timers To Add “free Play” Functionality To Classic Arcade Machines

January 7, 2012 by Mike Nathan 22 Comments

freeplay-arcade-board

[John Zitterkopf] is in the middle of restoring a vintage Sega Star Trek Captain’s Chair arcade game for the upcoming 2012 Texas Pinball festival, though one prerequisite for the show is that the game supports some sort of free play mode. At this point he doesn’t have the option of tracking down a freeplay ROM for the device, so he had to come up with a solution of his own.

He did not want to alter the machine’s operation in any significant manner, and this meant preserving the functionality of the coin chutes. To do this, he put together a small circuit that uses a pair of cascaded 555 timers to provide the machine with the proper signaling to simulate coin insertion, while still accepting coins. You might initially think that this could be easily accomplished by shorting a pair of contacts in the coin chutes, but as [John] explains, the process is a tad more complex than that.

If you have some old arcade games kicking around and are looking for a non-invasive way to make them free to play, be sure to check out his site for schematics and a complete BoM.

Ancient Mouse Teardown And Repair

January 7, 2012 by Brian Benchoff 24 Comments

For a young geek in the 80s, the it computer was the IBM PCjr. On paper, it was a truly remarkable leap in technology. With a wireless keyboard, light pen, and optical mouse it was an impressive, if maligned, piece of hardware. There was a small problem with the optical mouse, though; it required a special mousepad. [Michael], a PCjr aficionado, decided to make his own optical mousepad. It works, and was a lot easier to build than finding a used one for sale.

The PCjr mouse used two photodectors – a red LED and photodector for the horizontal axis, and an IR LED setup for the vertical. Light is shot through two holes in the bottom of the mouse and reflects back onto the photodetectors. [Michael] emulated the old mousepad with a sheet of aluminum foil and a transparency with a printed grid pattern. Surely not as elegant as an original, but it does the job nonetheless.

This clever-for-its-day optical mouse setup wasn’t limited to the lowly PCjr. A number of old Sun workstations had a similar setup that used small dots on the mousepad. There were several generations of mousepads that were generally incomparable with each other (because one type of mousepad wasn’t proprietary enough for Sun), but we would assume a similar build would work for these forgotten mice.

Thanks to [josh] for sending this one in.