AVR Controlled RGB LED Matrix Plays Tetris

November 9, 2010 by Mike Szczys 9 Comments

[Stan] built this LED matrix using a 16×16 grid of RGB LEDs. He built the hardware and wrote some subroutines to randomize the colors. He’s not using PWM because frame buffering is not feasible for the 1k SRAM limit of the ATmega168 he used. Instead, shift registers drive the lights which can be mixed to achieve eight different colors (including off for black) reducing the framebuffer size to just 96 bytes. After he got done with the build he realized this is sized well for a game of Tetris. We’ve seen AVR tetris, PIC Tetris, and Tetris using composite video but it’s always a pleasure to see a new display build.

After the break we’ve embedded [Stan’s] demo video, several pictures, and a schematic. He’s using many of the same principles outlined in our How to Design an LED matrix tutorial.

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Machine Your Own Ring Light

November 9, 2010 by James Munns 18 Comments

[Alan] acquired a stereo microscope from eBay, and decided to save some more money by designing, machining, and assembling his own ~~arc reactor~~ ring light to go along. After finding an LED driver board sitting around as well as ordering some surface mount LEDs, he set about using a lathe to cut away a block of lexan, making sure to include slots for the lights as well as the microscope mount point. Follow the link to see the detailed build photos, as well as some comparison shots with and without the ring light.

A month or two earlier though, and [Alan] would have had a fantastic start to an Iron Man costume.

70 LED Matrix In A Jack-o-lantern

October 26, 2010 by Mike Szczys 23 Comments

What takes eight hours to solder and uses more shrink tubing that you thought imaginable? An LED matrix installed in a real pumpkin. When I mentioned that we’d like the LED pumpkin in last Friday’s post scaled up to a full LED matrix I had no idea it would be me doing the work. But [Caleb] and I thought it might be just the thing to present for the hacker’s favorite holiday.

Installed in the autumn vegetable is a marquee made from a 5×14 matrix of light emitting diodes. I spaced them by printing out a grid on the computer, taping it to the pumpkin, and drilling 70 holes in the front of the thing. The real trouble came when inserting all of the LEDs from the inside; each of them has four wires soldered to it, creating a net of black wiring. Above you can see it turned out great. This is a shot of it scrolling the message HAPPY HALLOWEEN.

Join us after the break for video of this prop. But we’re not just sharing the finished product. I’ll take you through the build process. Along the way you’ll learn the design considerations that go into an LED matrix and how you can use these techniques to build your own in any size and configuration you desire.

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Lightsaber Color Selector

October 24, 2010 by Mike Szczys 11 Comments

[George Hadley] developed a nice setup to control the color of a replica Lightsaber. A small PCB houses a PIC 18F2221 and three switching transistors for the colors. A powerful LED resides in the tip of the handle, lighting up the diffuser that makes up the blade. But our favorite part is the control scheme. He’s embedded a small RGB LED in the handle, giving feedback as to which color of light can currently be adjusted (red, green, or blue). One button scrolls through the colors and a slide potentiometer adjusts that them.

We wouldn’t go as far as calling this a Halloween prop, we think it’s better suited for serious replica builds. But it would make an amazing addition to the little one’s costume. See it in action after the break.

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RGB LED Headband

October 23, 2010 by Caleb Kraft 20 Comments

Hard to imagine this going on business trips to Shangai

[Johncon] wrote this fantastic instructible showing us how to make an RGB LED headband. This should come in really handy the next time we find ourselves needing one… it happens. He picked up this little RGB LED strip while on a business trip to Shanghai. He had to reverse engineer the chip that controls each pair, but once that was done there wasn’t much left to do. He’s using a picaxe microcontroller since he had some lying around and, as he points out, they require very little external hardware.

He says he’s going to be ordering more of this LED strip soon and is willing to make a group buy if anyone is interested.

[via MakeZine]

Larson Scanner Hacking

October 14, 2010 by Caleb Kraft 13 Comments

more MORE MOOOORRREEE

We all love a good larson scanner. They’re so iconic that Evil Mad Scientist Laboratories makes a kit. However, just getting a kit and building it isn’t enough for many of us. How would we make a larson scanner better? Simply by adding more. EMSL shows us how you can modify their kit in both hardware and code to chain them together. They detail the modifications very clearly and show some video examples. You can see a three larson scanner chain in action after the break.

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Creepy HDD Activity Lights Just In Time For Halloween

October 11, 2010 by Caleb Kraft 23 Comments

We almost skimmed right past this spooky HDD activity light thinking it was just another set of LEDs wired to the motherboard. However, they explained right off that they didn’t want just another blinking light on their case. They wanted it to change its intensity smoothly based on hard drive activity. While there are a million ways this could have been over engineered, we think they did a pretty good job of simplifying the circuit. The bill of materials is pretty much just a handful of resistors, LEDs, an opto isolator, and a capacitor. The effect, is quite nice and can be seen in the video after the break.

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