Touch Screen Jukebox

We went “live” with our forums less than 24 hours ago and we already have our first project ready for the front page.  [Elementix] has shown us his touch screen jukebox build. Using an assortment of car audio speakers and amplifiers hooked up to an old Pentium 4 PC with 120 Gigs of storage, he put together the base cabinet. The touchscreen is an ebay find and he built a custom enclosure for that part. For the interface, he started with “Jukebox Arcade”, a jukebox front end for mame cabinets but found he could easily manipulate the layout since it used an xml file for the settings. After some trial and error, and a little work with the gimp, he got it looking the way he wanted. If you haven’t been there already, you should really check out our new forums.

Intermediate Concepts: Building Discrete Transistor Gates

[Simon Inns] has put together a lesson in digital logic which shows you how to build your own gates using transistors. The image above is a full-adder that he fabricated, then combined with other full adders to create a 4-bit computer.

Don’t know what a full adder is? That’s exactly what his article is for, and will teach you about binary math and how it is calculated with hardware. There’s probably at least a week’s worth of studying in that one page which has been further distilled into the five-minute video after the break. Although building this hardware yourself is a wonderful way to learn, there’s a lot of room for error. You might consider building these circuits in a simulator program like Atanua, where you can work with logic gate symbols, using virtual buttons and LEDs as the outputs. Once you know what you’re doing with the simulator you’ll have much more confidence to start a physical build like the one [Simon] concocted.

Finding this project a little too advanced? Check out our Beginner Concepts articles to help get you up to speed.

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Outside-air Cooled PC

[Brian] came up with an interesting PC cooling setup. He lives up north where it’s chilly in the winter. Using a bit of dryer ductwork and he was able to harness the outside air to cool his box. The system uses a window insert along with a dryer hood to suck in the outside air with a PC fan. We hope the air is adequately warmed, as it is exhausted into the room. Join us after the break for more pictures of his setup.

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Gaming On An IBM XT Using An NES Controller

[Frode] felt that using the keyboard for gaming on his old IBM XT computer was simply too noisy. He came up with a much quieter way to game by building an XT adapter for an original NES controller. If you haven’t explored the communication protocol used by the NES peripherals this is a great way to learn. Inside you’ll find a CMOS shift register that captures button states when it receives a latch signal. With that in mind [Frode] came up with a circuit to gather the bits from the controller, and generate input commands using the XT keyboard protocol without using a microcontroller. All of this is explained in the demo after the break.

Most of the NES controller hacks we see permanently alter the hardware. It’s nice to see one used without cracking it open.

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Peer Network Using Graphing Calculators

These calculators are networked together, able to pass information and play games on a multi-screen playing field. All of this is thanks to [Christopher Mitchell’s] work on a package called CalcNet. This networking software takes advantage of [Christopher’s] shell and GUI for TI calculators called Doors CS. To demonstrate the high reliability and throughput of his network he wrote NetPong, a multi-calculator version of the popular game that you can watch in a clip after the break.

This is definitely an instance where asking ‘why?’ is the wrong question. We’re more interested in the how, a question you can answer for yourself by reading the whitepapers he provided in both of the links above. [Christopher] knows what he’s doing, he proved that with his face-recognizing augmented reality.

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Chat List Indicator Uses Hacked Xmas Lights

Here’s a way to display which friends are logged into chat. This uses the same G-35 hacked Christmas lights we saw earlier in the month. [Andrejk’s] company uses Microsoft Lync as their chat protocol when working in teams. The service has an SDK that allowed him to write some .NET code to check status and display it on the string of lights. It works much as you would expect; red for busy, green for available, purple is out-of-office, and we’d guess that yellow is for away. Watch him demonstrate the system after the break.

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Update: 6809 Computing

[Matt Sarnoff] is designing his own 8-bit computer from scratch. This means not only designing the hardware but also writing his own kernel and custom libraries. Since we last saw this 8-bit machine hes added both video and sound output which has allowed him to start developing some software for his computer (see it play Conways game of life after the break).

Sticking with the retro theme of his computer he uses a TMS9918 chip to output the video and a YM2149 for audio. The YM2149 was the audio chip used in the Atari ST allowing him to play songs generated for that system with a little bit of hacking to account for the fact that the Atari ST ran at 8MHz where his Motorola 6809 only runs at 2MHz.

Via [Retro Thing]

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