The Coolest Homebrew Computer Gets Its Own Case

February 27, 2013 by Brian Benchoff 26 Comments

SONY DSC

When you’re building one of the best homebrew computers ever created, you’ll also want a great case for it. This was [Simon]’s task when he went about building an enclosure for his Kiwi microcomputer.

We were introduced to the Kiwi last year as the end result of [Simon] designing the ultimate computer from the early to mid-1980s. Inside is a 68008 CPU, similar to the processor found in early Macs and Amigas, two SID chips taken from a Commodore 64, Ethernet, support for IDE hard drives and floppy disks, and a video display processor capable of delivering VGA resolution video at 32-bit color depth. Basically, if this computer existed in 1982, it would either be hideously expensive or extraordinarily popular. Probably both, now that I think about it.

The case for the Kiwi was carefully cut from ABS sheets, glued together with acetone, and painted with auto body paint by a friend. It’s a great piece of work, but the effort may be for naught; [Simon] is reworking the design of his Kiwi computer, and hopefully he’ll be spinning a few extra boards for everyone else that wants a piece of the Kiwi.

Rube-Goldberg Provides Liquid Refreshment

February 19, 2013 by Mike Szczys 13 Comments

rube-goldberg-soda-machine

The image to the left doesn’t make this look like much, but inside of the cardboard vending machine lives a clever Rube-Goldberg device. The video after the break gives a look at the inner workings to show how a quarter manages to dispense a full can of Coke. But that’s about all the detail we get on the project.

There are two sets of counterweights used in the design. Some marbles, and what look like giant pinballs. The coin chute, located on the left side of the venting machine, funnels the money into the waiting marble. When the marble rolls off it lands on a spoon. The weight rotates the spoon-filled disk and causes one of the waiting pinballs to drop from their rack. As that metal ball falls it operates a ratcheting system to dispense just one can. It looks like the capacity of the machine is limited to two refreshing cans of sugary liquid, but that could be scaled up if more room were made for cans and counterweights alike.

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Speech Synthesizing Valentine From 1991

February 18, 2013 by Brian Benchoff 21 Comments

Internals

Back in 1991, a young [Backwoods Engineer] and his new wife went to a Valentines day get together. One of the conditions of the shindig was having the guys make – not buy – a Valentines day card. Go big or go home, he though, and after a few days he had a talking Valentines day card that would become one of his wife’s most treasured possessions.

The early 90s were a different time; in case you haven’t yet been made to feel very old yet today, 1991 is closer to 1970 than 2013 is to 1991. Likewise, the circuitry inside this heartfelt talking token of appreciation bears more resemblance to something from a 1970s electronics magazine than an Arduino project of today.

The project is powered by an old Intel MCS-48 microcontroller attached to one of the old speech synthesis chips Radio Shack used to sell. These are, in turn, connected to a programmable logic chip and a masked ROM that translates English words into phonemes for the speech synthesizer.

The entire device is constructed on a hacked up piece of perf board and a few wire wrap sockets; sturdy construction, even if the battery compartment has been replaced a few times.

As for what the talking valentine says? “”OK! Hello, I am a Talking Valentine Card. “Love Is A Many-Splendored Thing” and in this case also needs batteries!” You can check that out after the break.

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Building A Six-channel Floppy Drive Synth From Start To Finish

February 13, 2013 by Brian Benchoff 27 Comments

floppy

We’ve seen scores of floppy drives play music, but never before have we seen a project as clean as [Rupert]’s Moppyduino. It’s an Arduino-based board that controls the stepper motors in six separate floppy drives, coaxing them in to playing music from a MIDI file.

The Moppyduino is more than just a convenient way to control the stepper motors in six floppy drives. It’s also a great example of what can be done with home PCB fabrication; the entire project was designed and constructed in [Rupert]’s workshop.

After designing the circuit, [Rupert] printed it out on a laser printer onto a plastic transparency sheet. This was transferred over to a copper clad board, etched, and drilled. After assembly, [Rupert] attached a USB FTDI controller to receive data converted from MIDI data with a Java app.

The end result – housed in a custom Corian enclosure – is one of the best looking floppy drive synths we’ve ever seen. You can check out the process of building this awesome instrument after the break.

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Building A Better NES

February 9, 2013 by Brian Benchoff 41 Comments

NES

The first model of the NES wasn’t all that great; just ask any one of the millions of six-year-olds who independently discovered blowing on a cartridge made it work. The second NES hardware revision, the top loader, was better but only had RF video output. These are the only two pieces of hardware that can play every single NES game, and even with years of hacking NES-on-a-chip devices, there’s still much to be desired.

[low_budget] over on the AtariAge forum decided he’d had enough of these hardware compromises and decided to build the first new NES hardware revision in 20 years. It’s got all the best features from both of its predecessors and a few new features not seen on any existing NES. There’s support for composite and RGB video generators, new and better amplifiers for the audio, no lockout chip, and a top loading cartridge slot to prevent bent pins on the 72 pin connector.

While [low_budget]’s prototype works, it only does so by salvaging the CPU and PPU from a working NES. There’s still much work to be done on the prototype, but even if we’ll have to destroy our beloved NES, we’d love to get our hands on one of these improved consoles.

Programming A 555 Chip

February 8, 2013 by Brian Benchoff 23 Comments

555

[Phillip] needed a way to trigger an input every 8 hours or so. This is a snap with a microcontroller with a proper timer, but he recently heard about a very cool programmable timer chip that’s also a 555. Of course CSS555 timer chip has an obscure programming interface, but that isn’t a problem when you can program it yourself with a parallel port.

The CSS555 timer chip (PDF…) is a strange little beast. It’s pin compatible with everyone’s favorite timer IC, but also has a programming mode that allows the output to trigger on every 1 cycle, every 10 cycles, and so on up to one output every million cycles. Basically, it’s a 555 with a huge programmable capacitor that only costs two bucks.

After building a programming circuit from a 74125 hex buffer chip, [Philip] connected his programmer to the parallel port of an ancient PC. For a little retrocomputing cred, he wrote a small app in Forth that pushes commands from the parallel port to the CSS555 chip, greatly increasing the time delay of the chip’s stock configuration.

It’s a neat build, and an awesome introduction to a really cool timer chip. Of course this could be easily replicated with a $2 microcontroller, but that wouldn’t give [Philip] the satisfaction of using a 555.

USB Apple ][ Disk Emulator

February 7, 2013 by Brian Benchoff 14 Comments

One of the most commonly frustrating things about having an old Apple ][ lying around in your basement or attic is the lack of software. While at one time in the late 80s you may have had your own copy of Oregon Trail, that disk is either lost or non-functional, and it’s pretty hard to get new disk images onto 5 1/4″ disks.

To solve this problem for himself, [Eric] came up with an Apple disk emulator. A project like this has been done many, many times over the last few decades, but [Eric] put his own twist on it: he doesn’t use a microcontroller. Instead, he used a simple USB FTDI device to talk to the Apple disk drive.

The FTDI device in question is a UM232H chip that takes a USB connection and turns it into an SPI bus. Of course the Apple ][ disk doesn’t speak SPI, so [Eric] needed to do a little logic conversion with a 74LS251 multiplexer and a 74LS161 counter.

In the video after the break, you can see [Eric] loading Apple disk images on a IIc from his new Intel Mac. It’s a neat build, but it’s not done yet: [Eric] plans on adding a microcontroller with an SD card, allowing just about every Apple ][ game every made to fit in your pocket. Yes, [Eric]’s project is quite similar to the A][ pocket serial host we saw just a bit ago, but this will hopefully have a lower component count.

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