Using Arcade Monitors With The Raspberry Pi

December 17, 2012 by 27 Comments

mame

Along with the growing popularity of the Raspberry Pi, we’ve also seen a related uptick in MAME arcade cabinet builds. Putting this $35 computer in an arcade cabinet makes a lot of sense, but connecting it to one of the monitors found in old arcade cabinets is a bit of a pain. Luckily, [Celso] figured out how to connect a Raspi to one of these 15kHz RGB monitors, making for a much more accurate emulation of old arcade classics.

The Raspi only has two video outputs – an HDMI port and an RCA composite jack. The old arcade CRTs have an RGB input, so directly connecting a Raspi to one of these CRTs is a no-go.

The solution comes from two converters: one to convert the HDMI output to VGA, and another video downscaler that takes the 31kHz VGA signal and translates it into a 15kHz RGB signal. [Celso] settled on the GBS-8100 video converter, a rather uncommon piece of kit that can fortunately be found on a few Chinese eBay auctions.

After connecting the old arcade cabinet power supply to the Pi, hooking up an audio amp, and converting the controls to USB, [Celso] has a very accurate MAME machine.

Electronically Controlled NFC Tag

December 17, 2012 by 20 Comments

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[Per] is replacing his car stereo with a Nexus 7 tablet. It’s a great modification to add GPS, navigation, and a good music player, but [Per] wanted to pause his tunes and tell the tablet to go to sleep with an NFC tag. This means building a an NFC tag he can turn on and off, an interesting problem to say the least.

The easiest way to do this is with a CMOS switch, but a chip like a 74HC4066 is overkill for a project this simple. What [Per] needed was a single CMOS switch, something he found and fabbed a board for.

Now, with a press of a button, [Per] can activate his NFC tag and pause the music in his new stereo. Check out the video of this electronically controllable tag after the break.

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ATTannenbaum

December 17, 2012 by 10 Comments

attiny

It’s that special time of year again where the smell of baking cookies fill the house and shopping mall parking lots are filled with idiots and very angry people. [Kevin] thought it would be a good idea to build an LED Christmas tree and ended up building a great looking tree that’s also very simple.

In the video, the imgur album, and the github, [Kevin] shows us the simplest way to make a color-changing LED Christmas tree. The circuit uses LEDs to drop the voltage and to provide a nice glow around the base of the tree. After that, it’s just an ATtiny13 and some LEDs in a very nice freeform circuit.

Of course, if LED Christmas trees aren’t your thing, [hb94] over on reddit created an LED menorah. Pretty nifty he used an 8-position DIP switch for the circuit. Let’s just hope someone gave him a soldering iron for the last night of Hanukkah.

Beautiful Tube Amp Uses A TV Tube

December 16, 2012 by 23 Comments

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Most audio tube amps we see use common tubes – usually a 12AX7 for the preamp and one of the more common power tubes such as an EL34.[Daniel], on the other hand, decided to build his own audio tube amp with a 13EM7, a tube originally used for a television’s vertical oscillator. The resulting project is a wonderful stereo amp that sounds really good, to boot.

[Daniel] picked up the idea of using a 13EM7 tube from [Fred Nachbaur]’s MiniBlok SET amplifier. This very tiny 1-watt tube amplifier uses a single tube originally designed for use in old, old televisions. The secret behind this build is the fact this tube is actually two triodes in one package; one side of the 13ME7 has tons of gain but not much power, making it perfect for a preamp. The other side has a lot of power, useful for delivering two watts of power into a speaker.

After [Daniel] etched a few boards for his amp, he milled out a piece of wood for the chassis. When everything was mounted he had an awesome looking stereo amplifier that also sounds great.

Displaying Text On Random Strings Of Christmas Lights

December 16, 2012 by 27 Comments

lights

With the help of a microcontroller, a few strings of GE Color Effect Christmas lights can be easily turned into a fully programmable LED strip, or if you are so inclined, a huge RGB LED display. [Hubbe] had a few strings of these Color Effect Christmas lights, but didn’t want to spend the time arranging his light strings in an array simply to get a programmable display. His solution to this problem – the Chaos Display – turns strings of Christmas lights randomly thrown on a tree into a fully programmable display capable of displaying text and images.

[Hubbe] was inspired by QC Co-Lab’s light wall powered by GE Color Effect lights. Having a huge RGB LED display is very cool, but requires building a frame for each of the Christmas light pixels. [Hubbe] had a different idea – just throw the lights on a tree and use a web cam to figure out where each Christmas light is on the display.

The actual build consists of six strings of Color Effect lights. After throwing them on the tree, [Hubbe] set his phone on a tripod to record an image for each individual light. With some computing power, he was able to create a virtual display made of tangled strings of Christmas lights.

You can see a video of [Hubbe]’s work after the break.

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[Bunnie] Builds A Laptop For Himself, Hopefully Us

December 16, 2012 by 76 Comments

 

 

[Bunnie Huang], creator of the Chumby and artisan of chips and electrons, is building his own completely open source laptop. It’s called the Novena, and is powered by a quad-core ARM CPU, it’s got enough bells and whistles to make any hacker happy including an on-board FPGA, dual Ethernet ports, and enough GPIO pins to do some crazy, crazy stuff.

[Bunnie]’s laptop is an attempt to create a completely open-source laptop capable of some light code development, and web browsing. Every single chip on [Bunnie]’s laptop has a datasheet available (without requiring an NDA, unlike the Raspberry Pi), meaning this laptop might be the beginning of a completely open source laptop.

Officially, this laptop is a one-off project made just for [Bunnie]. He’ll be spending the next few months validating all features on the board and making a proper case. [Bunnie] says a few people may be interested in their own Novena (smart one, that guy), so he might consider a Kickstarter campaign in a few months. Don’t expect it to be cheap, but if you’d like to try your hand at making your own, all the files are up on the Novena wiki.

 

Solving A Rubick’s Cube With LEGO And Popsicle Sticks

December 15, 2012 by 20 Comments

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We’ve seen automated Rubick’s Cube solvers before, but never one that has garnered as many awards as [James]’ popsicle stick and LEGO Rubick’s Cube solver.\

To keep the project complexity down, [James] opted not to use a webcam to detect the color pattern on each face of the cube. Instead, he wrote a little Python app to manually enter the pattern on each face before letting his algorithm loose on the cube and calculating how to solve it.

So far, [James] has seen a huge amount of success from his project. He entered it in the New Zealand Brightsparks competition netting him $1000. This competition led to a win in the Realize the Dream science competition where he won a major prize and an entry into the International Taiwan Science Fair held early next year. An awesome accomplishment from a budding hacker, and we can’t wait to see what he comes up with next.

You can check out a video of [James]’ cube solver after the break.

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