LED Array Uses Ridiculous Amount Of 14-segment Displays

September 23, 2012 by Brian Benchoff 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.

Communicating With A Beam Of Light

September 22, 2012 by Brian Benchoff 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.

Using An Undocumented Display With An FPGA

September 19, 2012 by Brian Benchoff 11 Comments

When [Mike] ran across a display on Deal Extreme with 8 seven-segment displays, 8 red/green LEDs, and 8 buttons, he knew it would find a good home in a future project. There was only one problem, though: except for an Arduino library, there was absolutely no documentation available for this display. Wanting to use this display with an FPGA board, [Mike] decided against bit-banging a protocol and ported the C++ code into a hardware implementation.

This Deal Extreme display, the TM1638, features enough seven-segment displays, LEDs and buttons to build something really cool, and surprisingly isn’t terribly hard to interface with a microcontroller. The TM1638 library communicates with the outside world via only three pins and a simple serial connection.

After figuring out what commands are sent to make the display turn LEDs on or off, [Mike] wrote a hardware implementation for his Digilent Nexys2 and Digilent Basys2. Now the display operates on an FPGA just like it does with an Arduino, and is a great tool for debugging HDL code for [Mike]’s FPGA.

Helmet Of Many LEDs Built For Burning Man

September 14, 2012 by Mike Szczys 54 Comments

This motorcycle helmet was heavily altered to accept all of the hardware that goes into driving that huge array of LEDs. [Brian Cardellini] built it to wear at burning man. He claims to have been in over his head with the project, but we certainly don’t get that feeling when we see the thing in action. It’s light on build details, but there are plenty of demo shots in the video after the break. The animation and fading action really gets started about a minute and a half into it.

One of the early frames of the video is a shot of the parts order webpage. Since it’s an HD clip we were able to glean a few bits and pieces from that. It includes a MAX7219 LED Display Driver and fifteen 25-packs of Blue LEDs. Now that chip is a great choice, and one of the later shots shows two of them on breakout board driven by an Arduino. The look is very clean since he carved out most of the helmet’s padding to make room for the electronics.

Continue reading “Helmet Of Many LEDs Built For Burning Man” →

Hacking The Peggy

September 13, 2012 by Eric Evenchick 6 Comments

Evil Mad Scientist Laboratories received an email from someone who wanted to hack their Peggy kit. This LED matrix kit has been featured on Hack a Day in the past, and provides hardware to set up a 625 LED matrix.

This user built an external array of LEDs that they wanted to drive with the Peggy hardware. There are a few options for making this happen. The first one is to run wires from each of the 625 LED footprints on the board. Each has an anode and cathode, so that makes for a total of 1250 wires to run. It turns out that people have actually done this with the Peggy in the past, using very fine wire.

EMSL suggests wiring the rows and columns instead. This way, only one wire is needed for each row and column, allowing a 25×25 LED grid to use 50 wires instead of 1250. They also explain how to expand the grid to a 30×20 LED matrix. It’s a good explanation of how the kit works, and how it can be expanded.

Photo [oskay]

4″ Seven Segment Displays Make A Fine Scoreboard

September 12, 2012 by Mike Szczys 5 Comments

[Blark] took a few parts and turned them into a simple scoreboard. The centerpiece of the build is a set of 4″ seven-segment displays. With those in hand it was just a matter of choosing a controller to feed them data, and developing a user interface.

He seems to have had some issues as he mentions having blown up two PIC chips while soldering. He transitioned to an ATtiny24 chip and everything seems to work quite well now. The user interface depends on two buttons, each increments the score for one half of the display and pushing both at once zeros the game score. The displays use shift registers to store data so they’re quite easy to control with AVR chips. Check out the demo video after the break.

The only problem here is that someone needs to be on the sidelines to increment the score. We’ve seen some more intricate designs that let you use a remote control or even a smart phone.

Continue reading “4″ Seven Segment Displays Make A Fine Scoreboard” →

More LED Madness!

September 12, 2012 by Jeremy Cook 5 Comments

So last week [Caleb] posted an article about hacking a floating LED ball. In response, here’s a couple simple LED hacks or repurposings that I’ve come up with recently.

LED Solar Glow Cube: If you’ve ever seen path lights lighting up people’s gardens or walkways you may have wondered what components they had in them and how they could be repurposed. As shown in this article, there’s not much too them other than a circuit board, rechargeable battery, and, of course, a solar panel. Combine this with some leftover foam with a hole in it, and you have the device pictured above. Really simple, but the results are pretty cool as seen in the video after the break.

LED Nunchucks: If you thought that wheel lights were only for actual wheels, than you haven’t seen these nunchucks built with some PVC pipe and acceleration-sensitive wheel lights. This may not be much of a “hack” in that they are quite easy to build, but the results are pretty neat, being fun to sling around or even for use in long-exposure photography. Check out the videos after the break of these nunchucks in action and of some LED light paintings that can be made with them. Continue reading “More LED Madness!” →