Year: 2012

LED Array Uses Ridiculous Amount Of 14-segment Displays

September 23, 2012 by 29 Comments

What do you do if you see a bunch of 14-segment LED displays for sale for a penny a piece? [Fritzler], when faced with that conundrum did what any of us would do – he bought 64 14-segment displays and built a huge 16×4 alphanumeric display (German, here’s the translation).

[Fritzler] found a cache of old East German 14-segment displays for €0.01 at electrobi.de (don’t bother, they’re out of stock), and the only thing he could think of was building a gigantic display. He used ULN2803 Darlington drivers for each LED module, but there was still the issue of controlling the entire display.

For that, [Fritzler] decided to make his 16×4 use the same protocol as the Hitachi HD44780 LCD controller. This meant [Fritzler] could wire up his gigantic, power-hungry display to a microcontroller as if it were a simple LCD display.

An amazing amount of work went in to the creation of this display, as evidenced by a pair of pictures showing what [Fritzler] had to solder.

Thanks [freax] for sending this one in.

Volumetric Display Projects 200 Million Voxels Per Second

September 23, 2012 by 42 Comments

Over the last four years, [Will] and [Gav] have spent their time creating a huge, high-resolution 3D display. The’re just about done with their build, so they decided to offer it up to the Internet in the hopes of people creating new 3D content for their display. They call their project the HoloDome, and it’s the highest resolution volumetric display we’ve ever seen.

The HoloDome operates by spinning a translucent helix around its vertical axis at 20 rotations per second. A pico projector above the helix capable of projecting 1440 frames per second (an amazing device by itself) displays 72 ‘z-axis’ frames for each of the 60 ‘x and y frames’ per second. The result is a 3D display with a 480 * 320 * 72 voxel resolution capable of displaying 20 frames per second.

This isn’t the first time we’ve seen a swept helix used as a volumetric display, but it is by far the highest resolution display of its type in recent memory. [Gav] and [Will] have put their HoloDome up on the Australian crowd-funded site Pozible if you’d like to buy your own, but thankfully the guys have included enough detail on the main site to reconstruct this project.

Check out the video after the break to see the HoloDome in action.

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USBPIC Controls Just About Anything

September 23, 2012 by 9 Comments

Over the last few years, [Michael] has been developing a PIC microcontroller board. He calls his project USBPIC, and with the addition of a few FET drivers, H-bridges, and LED drivers his homemade dev board can handle just about anything thrown at it.

[Michael]’s board is build around a PIC18F2455 microcontroller with both an In Circuit Serial Programming header and support for a USB port included. Instead of going for a modular format where the board can expanded through shields or expansion cards, [Michael] decided to make three different versions of the USBPIC.

The TRANS USBPIC includes eight FETs for switching off high current devices totaling 32 Amps. The MATRIX board has twice as many outputs as the TRANS board, but uses ULN2803 or UDN2982 chips for driving smallish-current devices. Finally, the HBSW board takes a TRANS board and replaces four FETs with a an L298 H-bridge chip for driving two DC motors.

For what [Michael] lost in modularity, we think he gained a very tidy microcontroller board capable of driving everything from robots to LED matrix displays.

Mechanical Donkey Kong Features Laser Cut Mario

September 22, 2012 by 4 Comments

[Martin] just sent in a project he’s been working on that takes Donkey Kong out of the realm of pixels and sprites and puts our hero Mario into a world made of laser cut plywood.

This mechanical version of Donkey Kong uses an Arduino stuffed into an old NES to control Mario jumping over ball bearing ‘barrels.’ The game starts with 12 of these barrels ready to be thrown by our favorite gorilla antagonist, which Mario carefully dodges with the help of a pair of servos.

This is only the first iteration of [Martin]’s mechanical version of Donkey Kong. The next version will keep the clever means of notifying the player if Mario is crushed by a barrel – a simple magnet glued to the back of the Mario piece – and will be shown at the UK Maker Faire next year.

Although [Martin]’s ideas for a mechanical version of Donkey Kong aren’t fully realized with this build, it’s already a build equal to electromechanical Pong.

Speech Recognition On An Arduino

September 22, 2012 by 33 Comments

Speech recognition is usually the purview of fairly high-powered computers chugging along at hundreds of Megahertz with megabytes of RAM. Bringing speech recognition to the low-power microcontroller you’d find in an Arduino sounds like the work of a mad scientist or Ph.D. candidate, but that’s exactly what [Arjo Chakravarty] did. He developed the μSpeech library for the Arduino to allow for speech recognition for a limited set of voice commands.

Where most speech recognition systems use FFT and very fancy math to determine what phonemes a user is saying, [Arjo]’s system does away with this unnecessary complexity in favor of using very, very basic integral and differential calculus.

From [Arjo]’s user guide for μSpeech (PDF warning) we can see it’s possible to connect a small microphone to the analog input of an Arduino and accept voice commands such as ‘left’, ‘right’, and ‘stop’. The accuracy is pretty good, as well – 80% if μSpeech is trying to recognize words, and 30-40% if μSpeech is programmed to recognize single phonemes.

Sadly we couldn’t find a demo video of μSpeech in action, but you’re more than welcome to grab it via github for your own project. Send us a video of μSpeech in action and we’ll put it up.

Communicating With A Beam Of Light

September 22, 2012 by 39 Comments

Last weekend, ARRL, the national association of amateur radio, held a contest called, “10 GHz and up” with the goal of communicating via radio or microwaves over long distances. [KA7OEI] and a few friends decided to capitalize on the “and up” portion of the ’10 GHz and up” contest by setting up a full-duplex voice link over a distance of 95 miles. They used the 478 THz band, also known as red LEDs and laser pointers.

With [Ka7OEI]’s friends [Ron] and [Elaine] perched atop a 5700 foot-high mountain near Park City, Utah, [Gordon], [Gary] and [KA7OEI] trudged up a hill about 10 miles north of Salt Lake City. With the help of a pair of 500,000 candlepower spotlights, the two teams found each other and began pointing increasingly higher power LEDs at each other.

The teams started off with 3 Watt red LEDs before moving up to 30 Watt LEDs and a photodetector at each end. Even though the teams weren’t working with a true line-of-sight – refraction of the atmosphere allowed them to transmit this far – they were able to transmit tone-modulated Morse and even full-duplex voice.

Not bad for a transmission that bends the FCC’s “275 GHz and up” amateur band to its breaking point.

Adding Famicom Audio Channles To An NES Without Messing Up The Console

September 22, 2012 by 25 Comments

[Callan Brown] wrote in to show us a really interesting NES audio hack. [Callen] decided that he wanted the full Castlevania III audio experience, which (without modifications) can only be had through the original Japanese Famicom console. [Callen] weighed a few adapter options, and instead decided to come up with his own.

The issue is that the Japanese Famicom and the American NES actually have a different cartridge connector. The change in hardware from a 60 pin to a 72 pin connector added “features” like the 10 pins connected directly to the expansion port (used for stuff like the teleplay modem, who knew). The other two additional pins are used by the annoying 10NES lockout chip. While they were at it, Nintendo decided to route the audio path through the expansion connector instead of the cartridge.

This means that the Japanese cartridges can’t pipe sound to the NES audio channel with just a pin adapter. Good news though, after sourcing a pin adapter hidden inside certain NES games (Stack Up, Gyromite), audio can easily just be pulled from the adapter PCB. This requires the more expensive Famicom Castlevania III cartridge (Akumajou Densetsu). To cleanly route the new audio cable out of his front loading NES [Callan] reuses the sacrificial adapter game’s cart to make some kind of unholy hybrid. To round it off [Callan] also goes over steps to flash a translated ROM to the Japanese game.

What difference could an extra two squares and a sawtooth make? Check out the sound comparison video after the jump! Thanks [Callan].

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