Rate Gyroscope Circuitry Explained

March 26, 2013 by Mike Szczys 26 Comments

rate-gyroscope-driver

Hackaday alum [Adam Munich] shot a tutorial video on using a rate gyroscope.

Here he’s showing off the really fancy piece of ancient (technologically speaking) hardware. It would have set you back about fifteen grand in the 1960’s (inflation adjusted) but can be had these days for around $30. What a deal! These are not small, or power efficient when compared to the components that go into smart phones or gaming controllers, but they’re a heck of a lot more accurate than the ubiquitous modern parts. That’s because a rate gyroscope — which is the gold cylinder on the left — actually incorporates a spinning motor and a way to monitor how it is affected by changes in gravity. The driver/interface circuitry for this gets hairy relatively fast, but [Adam] does a solid job of breaking down the concept into smaller parts that are easy to manage.

Wondering what is different about this compared to a MEMS accelerometer? We know they’re really not the same thing at all, but wanted a chance to mention [The Engineer Guy’s] video on how those parts are made.

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Atari 800 EPROM Cartridge Hack

March 22, 2013 by Mike Szczys 5 Comments

atari-800-eeprom-hack

[FozzTexx] had an old Atari 800 collecting dust and decided to pull it out and get to work. The problem is that it’s seen some rough storage conditions over the years including what appears to be moisture damage. He’s read about a cartridge called SALT II which can run automatic diagnostics. Getting your hands on that original hardware can be almost impossible, but if he had a flashable cartridge he could just download an image. So he bought the cheapest cartridge he could find and modified it to use an EPROM.

When he cracked open his new purchase he was greeted with the what you see on the left. It’s a PCB with the edge connector and two 24-pin sockets. These are designed to take 4k ROMs. He dropped in an EPROM of the same size but the pin-out doesn’t match what the board layout had in mind. After following the traces he found that it is pretty much an exact match for an Intel 2764 chip. The one problem being that the chip has 28-pins, four too many for the footprint. The interesting thing is that the larger footprint (compared to the 2732) uses all the same pins, simply adding to the top and moving the power pins. A small amount of jumper wire soldering and [FozzTexx] is in business.

Playing MAME Games On A RGB Laser Projector

March 12, 2013 by Eric Evenchick 28 Comments

Vector based displays were used for arcade games in the ’70s and ’80s. A typical CRT uses raster graphics, which are displayed by deflecting a beam in a grid pattern onto a phosphor. A vector display deflects the beam in lines rather than a full grid, drawing only the needed vectors. Perhaps the best known vector game is the original Asteroids.

[Jeremy] built up a RGB laser projector, and wanted to run some classic arcade titles on it. He started off by using the XMAME emulator, but had to modify it to communicate with the laser and reduce flicker on the display.

To control the laser, a modified version of OpenLase was used. This had to be enhanced to support RGB color. The modified sources for both the MAME emulator and OpenLase are available on Github.

[Jeremy]’s friend, [Steve], even got a vector based game that he wrote working on the system. “World War vi” is a shoot-em-up battle about the vi and emacs text editors.

The results of the build are shown in a series of videos after the break.

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Making A Commodore 64 Portable

March 8, 2013 by Mike Szczys 20 Comments

making-a-c64-portable

This is [Wpqrek’s] Commodore 64 modified to go on the road with him. The elderly machine has a special place in his heart as it was what he learned to code on. He performed a series of hacks which house everything necessary to use the machine inside the original case.

Obviously the hack that has the most effect when it comes to portability was swapping a display for the small LCD mounted above the number keys. This was a pretty simple process because the screen, originally intended for a rear view camera in a vehicle, already had a composite video input. To emulate the floppy disc drive he’s using an SD card via an sd2iec board which he laid out himself. Rounding up the alterations is a stereo SID. The second channel uses the pre-amp circuit cut from a second C64. This audio hardware will let him do cool things like playing some classic Zeppelin.

You can get a video tour of these alterations after the break.

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Printed Machine Does Nothing Until The Heat Death Of The Universe

March 8, 2013 by Brian Benchoff 43 Comments

machine

A 2:1 gear reduction slows down a spinning shaft to half speed and doubles the torque. Repeat this a few times, and you’ve got a ludicrous amount of torque moving too slowly to see with even precision instruments. That’s the idea behind [Jeshua]’s project, a Printed Machine partially embedded in a block of concrete.

[Jeshua]’s build is a replica of one of [Arthur Ganson]’s kinetic sculptures. [Ganson]’s machine uses 50 sets of gears to reduce the rotation of 200 RPM motor more that 200 quintillion times. The final gear in the sculpture is embedded in a block of concrete, waiting to be freed by either erosion of the concrete block or the sun going nova.

Instead of metal gears, [Jeshua] used 3D printed gears in PLA. After assembling them on a stand, he cast concrete around the final, barely moving gear. It’s an impressively useless build that will turn to dust before the final gear makes even 1/10th of a revolution. This machine could have a longer life if it were printed with ABS instead of PLA, but with the time scales we’re talking about here it won’t make much difference.

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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