Building A CRT And Bathing Yourself In X-rays

July 12, 2012 by Brian Benchoff 15 Comments

For the Milan design week held last April, [Patrick Stevenson Keating] made a cathode ray tube and exhibited it in a department store.

The glass envelope of [Keating]’s tube is a very thick hand-blown piece of glass. After coating the inside of the tube with a phosphorescent lining, [Keating] installed an electrode in a rubber plug and evacuated all the air out of the tube. When 45,000 Volts is applied to the electrode, a brilliant purple glow fills the tube and illuminates the phosphor.

Since the days of our grandfathers, CRTs have usually been made out of thick leaded glass. The reasoning behind this – and why your old computer monitor weighed a ton – is that electron guns can give off a substantial amount of x-rays. This usually isn’t much of a problem for simple devices such as a Crookes tube and monochrome CRTs. Even though [Keating] doesn’t give us any indication of what is being emitted from his tube, we’re fairly confident it’s safe for short-term exposure.

Despite being a one-pixel CRT, we can imagine using the same process to make a few very interesting pieces of hardware. The Magic Eye tube found in a few exceptionally high-end radios and televisions of the 40s, 50s, and 60s could be replicated using the same processes. Alternatively, this CRT could be used as a Williams tube and serve as a few bits of RAM in a homebrew computer.

You can check out the tube in action while on display after the break, along with a very nice video showing off the construction.

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Tearing Through Floppy Drives To Build A Small-format Dot Matrix Printer

July 9, 2012 by Mike Szczys 26 Comments

The accuracy which [Mario] achieved in his pen plotter dot matrix printer is very remarkable. He tore through a pile of floppy drives to get the parts he wanted, and chose to go with a fine-point Sharpie marker as a print head. In the video after the break he flatters us with a printout of the Hackaday logo, but you also get a look at one problem with the build. The ink doesn’t always flow from the felt tip and he has to coax it (almost like priming a pump) with a piece of scrap paper.

He was inspired by the pen printer we featured back in June. This rendition features a printing area of 1.5×1.5 inches that can accommodate 120×120 black and white pixels. He’s not a microcontroller type of guy and is driving the printer from the parallel port of his computer.

The best printing technique puts the pen down and moves it around just a bit (helps prevent the ink flow problem we mentioned earlier) and produces images like one in the lower right. We love the 8-bit nature of the result and would use this all the time to make our own greeting cards.

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Refurbing A C64 With A Raspberry Pi

July 9, 2012 by Brian Benchoff 27 Comments

When [Carl] first heard of the Raspberry Pi, he immeidatly though how freakin tiny this board is compared to a Mini ITX motherboard. After ordering a Raspi, [Carl] decided to put his barely-larger-than-a-credit-card computer inside a Commodore 64.

[Carl]’s updated C64 functions exactly like the original – the 30-year-old keyboard works thanks to the help of a Keyrah keyboard and control port adapter. This adapter was soldered to a stripped USB cable, allowing [Carl] to keep the finished project looking very clean and tidy. Of course, the composite, HDMI, and Ethernet ports are broken out, allowing for this computer to connect to any network or TV.

For a final touch, [Carl] painted the case. He originally wanted to spray on a black, red, and purple motif to match the Raspi, but he eventually settled on a beige and red style. [Carl] really put together an awesome build, and for much, much less money than the rereleased C64 Windows-powered monstrosity goes for. You can check out the build log video after the break.

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Reverse Engineering Silicon

July 5, 2012 by Mike Szczys 16 Comments

[John McMaster] is doing some pretty amazing work with figuring out how the circuitry in an integrated circuit works. Right now he’s reverse engineering a serial EEPROM chip one section at a time. This is a 24c02 made by ST, and he chose this particular portion of the die to examine because it looked like there were some analog components involved.

He removed the top metal using hydrofluoric acid in order to take this image. By continually removing layers this way he manages to work out the traces and even the components themselves. To help clarify the parts he uses the set of snapshots to generate a colored map using Inkscape. From there he begins labeling what he thinks the components might be, and like a puzzle the pieces start falling into place one by one. From the Inkscape drawing he lays out a schematic, then rearranges the components to make the design easier to understand. Apparently this is a Schmidt trigger.

[Thanks George]

Levitating Lightbulb Does It All With No Wires

July 3, 2012 by Mike Szczys 58 Comments

It would be really fun to do an entire hallway of these levitating wireless lights. This a project on which [Chris Rieger] has been working for about six months. It uses magnetic levitation and wireless power transfer to create a really neat LED oddity.

Levitation is managed by a permanent magnet on the light assembly and an electromagnetic coil hidden on the other side of the top panel for the enclosure. That coil uses 300 meters of 20 AWG wire. A hall effect sensor is used to provide feedback on the location of the light unit, allowing the current going to the coil to be adjusted in order to keep the light unit stationary. When working correctly this draws about 0.25A at 12V.

Wireless power transfer is facilitated by a single large hoop of wire driven with alternating current at 1 MHz. This part of the system pulls 0.5A at 12V, bringing the whole of the consumption in at around 9 Watts. Not too bad. Check out [Chris’] demo video embedded after the break.

A similar method of coupling levitation with power transfer was used to make this floating globe rotate.

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Dueling Mechanical Bulls

July 3, 2012 by Mike Szczys No comments

Do you have what it takes to stay on the mechanical bull longer than the next guy? Who cares! We want to know if you’ve got what it takes to build your own dueling mechanical bulls. After seeing the development stages in the video after the break we think you’ll agree that the construction part of the project is way more fun than the ‘sport’ that results. But still, we can’t watch the competition without beaming with delight too.

The project was developed by the Madagascar Institute, an Art Collective out of Brooklyn, New York. The scene displayed above is the installation at this year’s Google IO conference, where two contestants could battle it out on the same hardware, being driven the same way, at the same time. You can make out a sign on the wall in the background. It acts as the scoreboard with two red arrows, one of which will light up to identify the loser when they have been thrown from the bull.

If only this had been driven with a Bullduino… maybe next year.

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Two Retro Successes With A Commodore 64

June 29, 2012 by Brian Benchoff 4 Comments

Slowly but surely, Hackaday readers have been logging onto our retro edition with some very old hardware. Of course we’re featuring the coolest as retro successes. [azog] and [logik] entered the pantheon of brave souls who loaded up Hackaday with a Commodore 64 this week, and their builds are pretty impressive to say the least.

[logik]’s build was nearly doomed from the start: he used a C64 found dumpster diving one day with a bad power supply and half-dead VRAM chips. The first order of business was getting the C64 talking to a PC with the help of a MAX232 serial IC and loading up 64HDD to transfer a copy of Novaterm. From there it was a simple matter of connecting to an Ubuntu box and pulling up our retro site with the help of a text-only web browser.

[azog] didn’t want to abuse Lynx with his submission so he connected a Commodore 64 Ethernet card and loaded up Contiki. The banner image (above) is the ASCII Hackaday logo rendered with the C64’s PETSCII character set, something I did not foresee when I created our retro edition. Still, freakin’ awesome.

As a small aside, we’re going to open up the comments for this post to suggestions and recommendations you’ve got for the Hackaday retro edition. What would you like to see? The Retrocomputing guide is woefully inadequate, we know, but there’s a project in the works (getting WiFi over a serial port on a 68k Mac) that should be well received.