Eye of the Tiger — As played by a Dot Matrix Printer


Do you have a big hackathon coming up? Need to start a training montage like Rocky? We don’t think you can get any more awesome than this Dot Matrix Printer that can play music!

The hack makes use of an old 24-pin dot matrix printer, which is now a MIDI compatible sound generator. It uses an Atmega8 and an FPGA connected to different parts of the original printer’s circuit board. The Atmega8 takes the incoming MIDI data and communicates it to the FPGA while driving the stepper motors for both the paper feed and print head. The FPGA on the other hand is responsible for the PWM to drive the individual printer pins. This means the printer can play up to 21 notes simultaneously, and it’s capable of taking in up to 16 MIDI channels, all with individual volume, pitch, and key velocity!

[MIDIDesaster] has several other musical examples of their printer in action, including the Duke Nukem theme, Hysteria by Muse (one of our favorites), and even the Wallace and Gromit theme!

It’s a similar project to this printer synth we shared almost 9 years ago! Stick around to get pumped up with Eye of the Tiger! But if you’re wearing headphones… turn the volume down.

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Introducing the SquareWear Mini, with its Chainable Color LED Matrix

[Ray] just tipped us about his latest project: the SquareWear Mini, which basically is an improved version of the SquareWear 2.0 that we featured a month ago. For our readers that may have missed it, the SquareWear is essentially a wearable Arduino platform running at 3.3V and 12MHz. Both versions are based on an ATMega328 microcontroller running the V-USB library to provide USB connectivity, put together with diverse onboard peripherals.

As you can see in the picture above, the Mini includes 2 N-MOSFETs, one temperature sensor, one light sensor, a 16KB EEPROM memory, one buzzer, a one cell LiPo battery connector together with one charging controller, and finally a power switch (USB/battery). It is supposed to be 25% smaller than the SquareWear 2.0 and is optimized to work with a WS2812B-based 5×7 RGB LED matrix that [Ray] also designed. The latter can easily be cascaded in X/Y directions with other LED matrices in order to expand the overall display.

At last, [Ray] created a software to design animations and upload them to the SquareWear . A presentation video of the complete system is embedded after the break and you can download all the design files on GitHub.

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LED Matrix Mask Will Scare Up Holiday Cheer

[Davide] sent us this fun LED matrix mask he built using an ATMega8 and 74LS595N shift registers. Each of the eyes is an 8×8 LED matrix, and the mouth is made from two 8x8s. [Davide] used a ULN2803A Darlington transistor array to drive the matrices.

When the user steps behind the mask, an IR sensor detects that a face is within range and activates the facial features. The code randomly runs the eye and mouth patterns. If the user starts speaking, a microphone element detects his voice and a separate speaking mouth pattern is executed.

The mask body and stand are découpaged with pages from Dylan Dog comics. [Davide] says he built the mask years ago, but decided to submit it to the 2013 Inverart Art Fair in Milan. As you can probably imagine, the mask has been a big hit with the kids so far. Stick around to see [Davide]‘s Santa-fied demonstration after the jump. [Davide] didn’t give us any details on that sweet hat, unfortunately.

If you require a better degree of protection or more LEDs, check out this LED helmet.

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Fubarino Contest: LED Matrix Game Console


A good amount of entries for our Fubarino Contest are finally starting to roll into the tip line. Good thing, too, as this is the last day for submissions. What are you waiting for? we just passed the entry deadline.

The latest one comes from [Vojtak], who created an awesome looking minimalist game console with nothing but the power of sheer will, impressive determination, and an Arduino. The 8×8 red LED matrix is driven by the wonderful Max7219 display driver, and a 3-axis accelerometer and battery charging circuit fills out the build. On the software side, [Vojtak] has written a number of apps for his console including Snake, a maze game, and a lot of stuff that uses the built-in accelerometer.

As an entry to our Fubarino Contest,  [Vojtak] needed to implement our URL as an easter egg. By entering the Konami code and going into the console’s image viewer, you have four additional slots to save your artwork which are initially filled with something resembling the title pic for this post. The most impressive easter egg for this submission comes from the maze game. At first glance, nothing looks weird, but after scrolling around the huge maze you can see “HACKADAY.COM” written with pixels. Remind us to do this when we build a hedge maze.

This is an entry in the Fubarino Contest for a chance at one of the 20 Fubarino SD boards which Microchip has put up as prizes!

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7-Segment Display Matrix Visualizes More Than Numbers


You can pretty much tell that this is an outstretched hand shown on a large grid of 7-segment displays. But the only reason you have to look twice is because it is a still photo. When you see the video below it’s more than obvious what you’re looking at… partly because the device is being used as an electronic mirror.

In total there are 192 digits in the display. To make things easier, four-digit modules were used, although we still couldn’t resist showing you the well-organized nightmare that is the wiring scheme. Each module is driven by its own discrete Arduino (driving 28 LEDs as they’re apparently not connecting the decimal point). All 48 Arduino boards receive commands from a Raspberry Pi which is running openFrameworks to generate the animations.

Now of course the project was well under way before [Peter] discovered a similar display from more than a year ago. But we’re glad that didn’t stop them from forging ahead and even building on the idea. They added a camera to the display’s frame which lets it mirror back whatever is in front of it.

What popped into our minds was one of the recent entries for the Trinket contest.

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An Impressively Large LED Matrix


One of the more impressive projects a home-bound tinkerer can pull off is some sort of display. Not only does the final project result in a lot of blinky, glowey things, but driving hundreds of LEDs is an achievement in itself. [Fabien] decided he wanted to build his own LED display and ended up with something great (French, Google translation).

Instead of going off the deep end and making his own boards for this giant LED display, [Fabien] found a very cheap 16×32 LED display board on DealExtreme. Once these kits were pieced together, [Fabian] mounted them in a wooden frame and started connecting the displays together.

The original plan was to drive these with an Arduino, but with so many pixels he quickly ran out of RAM. Replacing the Arduino with a larger ATMega1284p, [Fabian] found the RAM he needed and started work on some interesting visualizations.

Of course, Conway’s Game of Life made a showing in the final build, but [Fabian] also managed to whip up a spectrograph using FFT. It’s a very nicely put together display that makes us want to buy a few of these displays ourselves.

Making a Diode Matrix ROM

Here is a nice project that allows youngsters (but also adults!) to actually see the data stored in a Read Only Memory (ROM). The memory shown in the picture above is made of diodes. [Scott] made it as a part of his Barcamp Fall 2013 presentation about visualizing ROMs. He starts his write-up by stating the obvious: this memory is not practical. Nonetheless, it still was a fun exercise to do. [Scott] then greatly described all the different kinds of read only memories that you can find out there, with a few words explaining how they work. In his diode ROM, bits are ‘programmed’ by adding (or not) a diode between a given data line (anode) and an address line (cathode). When pulling low a given address line, the corresponding data line will only be pulled low if a diode is present. [Scott] finally checked his circuit by using a very old device programmer which could only be run in DOS.