Light Pen Draws on LED Matrix

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Who needs a 1920×1080 OLED display when you can have an 8×8 matrix of LED goodness? That’s the question [Kathy] asked when she built this LED matrix light pen project. It looks simple enough – a 64-LED matrix illuminates as the pen draws shapes. But how does the circuit know which LED is under the pen? Good old fashioned matrix scanning is the answer. Only one LED is lit up at any time.

[Kathy] used a pair of 74LS138 3-to-8 line decoders to scan the matrix. The active low outputs on the ‘138 would be perfect for a common cathode matrix. Of course [Kathy] only had a common anode matrix, so 8 PNP transistors were pressed into service as inverters.

The pen itself is a phototransistor. [Kathy] originally tried a CdS photoresistor, but found it was a bit too slow for matrix scanning. An LM358 op-amp is used to get the signal up to a reasonable level for an Arduino Uno to detect.

The result is impressive for such a simple design. We’d love to see someone use this platform as the start of an epic snake game.

Filed Under: led hacks Tagged With: , , ,

Network Controlled Decorative LED Matrix Frame

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LED-Pixel-FrameThere is nothing better than a project that you can put on display for all to see. [Tristan's] most recent project, a Decorative LED Matrix Frame, containing 12×10 big square pixels that can display any color, is really cool.

Having been built around a cheap IKEA photo frame this project is very doable, at least for those of you with a 3D printer. The 3D printer is needed to create the pixel grid, which ends up looking very clean in the final frame. From an electronics perspective, the main components are a set of Adafruit Neopixel LED strips, and an Arduino Uno with an Ethernet shield. The main controller even contains a battery backup for the real time clock (RTC) when the frame is unplugged; a nice touch. Given that the frame is connected to the local network, [Tristan] designed the frame to be controlled by a simple HTML5 interface (code available on GitHub). This allows any locally connected device to control the frame.

Be sure to check out the build details, they are very well done. If you are still not convinced how cool this project is, be sure to check out a video of it in action after the break! It makes us wish that you could play Tetris on this frame. Very nice job [Tristan]!

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Filed Under: Arduino Hacks, led hacks Tagged With: , , , , , , , ,

Aluminum LED Matrix Looks Professionally Made

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[David Donley] has wanted to make a LED matrix for a while now, and has decided to finally pull the trigger — after all, that many LEDs certainly aren’t cheap!

He’s using a set of 16 Adafruit 8×8 NeoPixel LED Matrices (almost $600 worth of LEDs) and a BeagleBone Black to control them. To mount the LED matrices he bought a sheet of 6061-T6 aluminum for two purposes — one to act as a giant heatsink, and two, to look cool. All he had to do was drill some holes in the sheet for the connectors, and then use 3M 300LSE double-sided adhesive to stick the NeoPixels to the surface. The result is a border-less display that looks clean and professional.

To power the array he’s using a 5V 90A power supply — at full brightness these LEDs can consume around 325W, or 65A at 5V!  Taking notes from the opensource LEDscape code on GitHub he’s made his own software to control the display — stick around after the break to see it in action.

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Filed Under: led hacks Tagged With: , , , ,

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

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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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Filed Under: musical hacks Tagged With: ,

Introducing the SquareWear Mini, with its Chainable Color LED Matrix

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[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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Filed Under: Arduino Hacks, wearable hacks Tagged With: , ,

LED Matrix Mask Will Scare Up Holiday Cheer

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[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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Filed Under: led hacks, Microcontrollers Tagged With: , , ,

Fubarino Contest: LED Matrix Game Console

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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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