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.

Power Protection Circuit Tutorial

January 4, 2012 by Brian Benchoff 17 Comments

Building your first circuit is empowering, but make sure it’s not too empowering. [Jon] sent in a great tutorial of power protection circuits to make sure you don’t release the mystical blue smoke that make electronics work.

There’s an in-depth tutorial of the classic series diode that’s the simplest of all power protection circuits. There’s not much to it – just a diode that provides reverse polarity protection. A fuse and parallel diode doesn’t have the voltage drop a series diode has, but doesn’t do anything for an overvoltage. A P-channel MOSFET gets around the problem of voltage drop, and [Jon] gives us some really nice empirical data to demonstrate his testing setup.

There’s a ton of nice write ups on [Jon]’s site that are perfect for getting ideas for projects like ten switches on one pin and some strange stuff [Jon] picked up at his Goodwill. If you’ve got any tutorials on general electronics, be sure to send them in on our tip line.

[Bob] Shows Us How To Make DIY Calendars For Vintage Computer Geeks

December 29, 2011 by Mike Nathan 1 Comment

[Bob Alexander] wrote in to share a hobby of his that we thought was pretty timely considering the new year is quickly approaching. For several years now he has put together a custom calendar for himself, including both dates he finds important along with sweet pictures of vintage computer equipment. Friends and family found his calendars so intriguing that they asked him to make some for them as well.

Each year his stack of calendar requests grew, and he found that no outlet – online or otherwise could produce exactly what he wanted. Instead of settling, he wrote a small application that lets him customize and print calendars to his heart’s content.

We think this is much cooler than buying one at your local bookstore, and we’re guessing that our readers likely agree. If you were creating your own custom calendar, what cool vintage computer hardware would you choose to display? What if you were designing a Hack-a-Day calendar? Let us know in the comments – we’re itching to find something interesting to look at while we count down to New Year’s Eve!

Ammo Tin ][

December 26, 2011 by Brian Benchoff 10 Comments

Ammo crate PCs have been around since Unreal Tournament LAN parties, but this one goes further back than that; [Simon] put an Apple II in an ammo crate. It’s a fitting anachronistic build from the same guy that built the TARDIS MAME cabinet.

Thankfully, [Simon] didn’t tear apart an Apple IIc for this build. A bare-bones Celeron motherboard was acquired for this project to run the AppleWin emulator. Instead of shoving all the parts into the box and calling it a day, [Simon] did it right and fabricated a very nice frame for the computer. With a wimpy CPU and no expansion cards, the Ammo Tin ][ can run very cool without drawing a lot of power.

We really have to hand it to [Simon] for this build. The metal work on this build looks great (it should for someone who is rebuilding an Austin 7), and we’ve got to respect the love for the Apple II. Now all that’s needed is a real Apple II keyboard on that USB port.