Barcode Challenge For Radio Operators

November 27, 2010 by Mike Szczys 32 Comments

[Scott Harden] came across a few posts about QR code matrix barcodes coming through on the 40m baud radio band. A few operators had captured the signals and assembled them into the code block seen above but they weren’t able to get a clear enough shot for a smartphone to decode the image. [Scott] took on the challenge and decoded the mysterious message himself. He tried some graphic editing to separate and enhance the color channels in order to up the contrasts of the image. This helped, but still couldn’t be read automatically. In a move similar to those seen in Hackaday’s own barcode challenges he dropped the image into Inkscape so that he could manually clean it up. Once it was overlaid on a grid the job was pretty simple. the left side did require some more image manipulation and precision”squinting” to eliminate interference from the vertical banding, but he managed to get the message. We won’t spoil it here in case you want to take on the challenge yourself. Good luck!

Communicating With An LED Matrix

November 19, 2010 by Mike Szczys 9 Comments

Most of the LED matrix posts we run delve into the hardware design. This time around [J Bremnant] used prefab modules and focused on writing code to address the display. The hardware combines two 24×16 LED boards from Sure Electronics with a Teensy 2.0 to drive the display and provide a USB connection. The firmware comes in just under 8k, leaving graphic manipulation up to a PC.

[J Bremnant’s] Python script offers a lot of flexibility when working with the display. There are three modes selectable through a terminal interface. One just tests the display and then drops into Conway’s Game of Life. The second mode lets you send commands via serial interface so it can be used as a message ticker. The final feature is frame addressing that allows graphics to be dropped into the display. See each of these featured in the video after the break.

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Build A Pong Gaming Console

November 17, 2010 by Mike Szczys 18 Comments

A lot of thought went into [Patrick Mccabe’s] Pong gaming console build. He used components we’re familiar with; an Arduino as a controller, 8×8 LED modules as the display, and potentiometers (with fancy knobs) in project boxes as the controllers. But every step along the way he took care to build this cleanly and robustly. Even the MAX7219CNG drivers for the six LED modules reside on PCBs from a fab house. The finished project is something you’d be proud to pull out and play when you have friends over. Even if they’re not part of the geek elite we think they’d enjoy a game or two. Great job [Patrick]. We hope to see an internalized microcontroller and scoring in your next update!

Want to do this but the cost of the matrix drivers scared you away? Follow our tutorial to build your own display using an AVR for the multiplexing.

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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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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Matrix Clock Is A Breadboarding Win

September 22, 2010 by Mike Szczys 23 Comments

Normally when we feature a clock made with a 32×8 LED matrix we’d load up an image of the display for the banner photo. But this time around we were so impressed by [JB’s] breadboard work we had to use this image. We see an ATmega168, three buttons, three LEDs, a piezo buzzer, 32.768 kHz crystal, smoothing capacitor, and a few resistors; everything he needed to keep time and display it on the matrix module. If this is just going to sit on your bookshelf for a while it’s a great alternative to point-to-point soldering on a protoboard. Nice work fitting it all on there [JB].

ATtiny2313 Prime Number Generator

August 24, 2010 by Mike Szczys 9 Comments

[Scott Harden’s] prime number generator exhibits a great way to use an LED matrix to present readable information. The project resides in a hinged wooden box with a grid of holes on the lid for the LEDs. [Scott] has overlaid the matrix with a printout showing powers of two that represent different prime numbers. Inside you’ll find an ATtiny2313 microcontroller that handles the column scanning and prime number testing. We’ve embedded a video the break where [Scott] explains the project in great detail, but you should also check out his prototyping and construction pages.

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