Johnny Mnemonic, Broken Columns, And Pinball Repair

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[Quinn Dunki] has come to realize the pinball machines of her youth aren’t the lame games she remembered. They’re actually quite marvelous in terms of electronics, mechanics, engineering and the all important hackability. Wanting to pick up a 90s dot matrix display pinball machine and being a [William Gibson] fan, [Quinn] picked up an old Johnny Mnemonic machine. She’s already looked into replacing the incandescent bulbs with LEDs, and has just wrapped up troubleshooting a broken plasma dot matrix display.

dotsThe neon dot matrix displays in pinball machines of this era are finicky devices with a lot of stuff that can go wrong. On powering the display up, [Quinn] noticed a few columns on the left side of the display weren’t working. These machines have great diagnostic menus, so running a test that displays a single column at a time revealed two broken columns. However, when a solid fill test was run, all the columns work, save for a few dots in the upper left corner. This is an odd problem to troubleshoot, but after more tests [Quinn] realized dots in column five and six only work iff both adjacent dots in the same row are lit.

The power supply seemed okay, leaving the problem to either a logic problem, or something wrong in the glass. With a meter, [Quinn] deduced there was a short between the two broken columns, and tracing every thing out revealed a problem in the hermetically sealed display filled with noble gasses. A replacement display was ordered.

While [Quinn] was replacing the display, she decided it would be a good time to rehab the almost-but-not-quite out of spec driver board for the display. The power resistors had scorched the PCB, but didn’t damage any traces. Replacing the parts with modern components with a higher power rating brought the board back to spec with components that should last longer than the 20-year-old parts previously inhabiting the driver board.

It was a lot of effort, but now [Quinn] has a brand new display for her pinball machine and is ready to move on to the next phase of her restoration.

Help Hackaday build a custom gaming controller for a good cause

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We are going to make a custom gaming controller for a child with Muscular Dystrophy. His name is Thomas and he loves minecraft. This is a project that I have been wanting to do for years.  I’m just beginning now, and you can join in on the project and offer your thoughts in our forums.  We’re starting with Thomas, but ultimately, we’d like to develop a collection of fairly simple to construct open source game controllers.

For people who have a physical disability, gaming can have a profound psychological impact. Sometimes it is the only place where they can go and be on a level playing ground with their peers.  Often custom gaming controllers are quite expensive, especially when you start to leave the standard xbox/playstation form factor.

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High speed video from cheap digital camera

Some researchers from Oxford University have come up with a way to produce high-speed video from a one mega-pixel camera. They’re calling the method Temporal Pixel Multiplexing. This method adds a digital micromirror device in line with the camera lens. These chips house over a million mirrors and can be found in home theater projectors. By placing one in front of the digital camera, a longer exposure can be used while the DMD redirects the light. This way, one high-resolution image actually contains multiple frames of lower-resolution video. The video is still decent quality and, at a far lower cost than common high-speed video equipment, this is a worthwhile trade off.

[Thanks Andrew via NewScientist]

Tiny projector teardown

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The team from Tech-On has taken the time to teardown two interesting microprojectors. The first model they tackled was the Optoma PK101. It’s based around a digital micromirror device (DMD) like those used in DLP. Separate high intensity red, green, and blue LEDs provide the light source. A fly-eye style lens reduces variations between images. They noted that both the LEDs and processors were tied directly to the chassis to dissipate heat.

The next projector was the 3M Co MPro110. It uses Liquid Crystal on Silicon (LCoS) technology. The light source is a single bright white LED. The projector seems to have more provisions for getting rid of heat than the previous one. The most interesting part was the resin polarizing beam splitter. It not only reflected specific polarizations, but also adjust the aspect ratio.

[via Make]