LED-Guided Piano Instruction


[Kay Choe] can’t play the piano. Rather, he couldn’t, until he converted his keyboard to include LED-guided instruction. [Kay] is a microbial engineering graduate student, and the last thing a grad student can afford is private music lessons. With $70 in components and a cell phone, however, he may have found a temporary alternative.

The build works like a slimmed-down, real-world Guitar Hero, lighting up each note in turn. We’ve seen a project like this before, with the LEDs mounted above the keys. [Kay]‘s design, however, is much easier to interpret. He embedded the LEDs directly into the keys, including ones above each black key to indicate the sharps/flats. An Android app takes a MIDI file of your choice and parses the data, sending the resulting bits into an IOIO board via USB OTG. A collection of shift registers then drives the LEDs.

For a complete novice, [Kay] seems to benefit from these lights. We are unsure whether the LEDs give any indication of which note to anticipate, however, as it seems he is pressing the keys after each one lights up. Take a look at his video demonstration below and help us speculate as to what the red lights signify. If you’re an electronics savant who wants to make music without practicing a day in your life, we recommend that you check out [Vladimir's] Robot Guitar.

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LED Pocket Watch

LED Pocket Watch

[Frank] wanted a classy way of telling the time, so he built up a LED Pocket Watch. The watch features 132 LEDs for displaying the time, two buttons to activate and change modes, a vibration motor, and a buzzer.

It’s controlled by a picoPower ATmega645P, which has enough pins to drive the array of LEDs, an internal real time clock, and low power consumption. The device is housed behind laser cut acrylic face, and sits in a 3D printed case.

To power the device, [Frank] used a rechargeable lithium coin cell battery. The charging circuitry is based on a MCP73831, which is an easy to integrate charge control IC. A USB connector is used to provide power to the board.

One of the bigger challenges of the design is driving the large array of LEDs. [Frank] uses Charlieplexing to group the LEDs and reduce the number of pins required. Another trick he used was offsetting the ISP header pins. This allows for programming the AVR without soldering a connector to the board.

[Frank]‘s Instructables write-up is very detailed, and includes explanations of the schematic, PCB layout, software design, and case design. It’s a good read that details his design decisions.

After the break, watch [Frank]‘s video overview of the project.

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Thinking Cap is also Party Hat

The Thinking Cap is a piece of wearable signage that lets you display what’s on your mind. The hat uses a Teensy 2.0 connected to a Bluetooth radio to allow the wearer to update the message on the fly, letting the room know what their thinking at that instant.

This hack is based off of LPD8806 controlled LED strips, which are becoming very popular for adding lots of LEDs to anything. There are five strips that need to be controlled over SPI, but the Teensy only has one SPI peripheral.

This lead to the use of multiplexer to allow for controlling each strip individually. The hat uses an interesting and low cost scheme to multiplex five channels using two 744052 dual 4 channel multiplexors and a 7400 inverter.

The Teensy can receive messages using the Bluetooth serial port protocol. The 5 x 7 pixel characters are stored in a framebuffer, and shifted around the hat to create the animation.

The result is a bright message circling around the user’s head, which can be updated with a smartphone over Bluetooth. Check out a video demo of the hat after the break.

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Toorcamp: Bliplace 2.0

We’ve shown [Tanjent]‘s Bliplace 1.0 in the past. He handed out a few hundred of the open source audio toys at Burning Man. At Toorcamp, he’s been showing off an improved 2.0 version of the project. This one has a more powerful microcontroller and many more RGB LEDs.

The device uses the ATMega328 and an electret microphone to sample ambient noise. It the processes the sound into a light pattern which is displayed on the line of RGB LEDs. The demo that I saw showed the LEDs synchronized to bass frequencies, which it could pick up at a range from the large sub-woofers at Toorcamp. It’s powered by a CR2032 coin cell battery, which means it can be worn as a neat audio toy.

This prototype version was etched in his kitchen but [Tanjent] is working on making a production version of the PCB. He plans to release it as a surface mount soldering kit.

Building an artificial moon for Burning Man


If you were lucky enough to score passes to this year’s Burning Man, be sure to keep a look out for [Laurence Symonds] and crew, who are putting together an ambitious fixture for the event. In reality, we’re guessing you won’t have to look far to find their giant moon replica floating overhead – in fact it will probably be pretty hard to miss.

They are calling the sculpture “Lune and Tide”, which of an 8 meter wide internally lit moon which hovers over a spinning platform that’s just as big across. The inflatable sphere is made up of giant ripstop nylon panels which are home to 36,000-odd sewn-in LEDs. The LEDs illuminate the sphere to reflect the natural color of the moon, though with a simple command, [Laurence] and Co. can alter the lighting to their heart’s content.

If Hack a Day’s [Jesse Congdon] makes his way out to the festival again this year, we’ll be sure he gets some footage of Lune and Tide in action. For now, you’ll have to satisfy your curiosity by checking out the project’s build log.

Musical light show is far less complex than you might think


[Matt and Jason Tardy], who make up the musical performance duo known as AudioBody, were recently featured on Make: explaining how they put on one of their trademark segments. The most popular portion of their show features color changing tubes of light which the pair spin and fling around not unlike a higher-tech version of the Blue Man Group. While the visuals are pretty slick, the technique behind it is far simpler than most people initially imagine.

As you can see in video below, the tubes look to be nothing more than simple white lights. As the brothers work through their performance however, the tubes switch from white to blue and back again with a liquid-like transition between the colors.

The [Tardys] say that most people peg a microcontroller or other complex electronics as the source of their light wizardry, but the real answer is much simpler. Embedded in the end of each tube is a bright LED flashlight. A sliding blue filter positioned inside the tube provides the silky smooth transition between colors – no fancy electronics required.

If you would like to see how they were built, be sure to swing by the AudioBody web site for a how-to presentation by the [Tardys] themselves.

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Tool box light dimmer helps out a friend, offers up design tips


[miceuz] has a friend that works as a theatre technician, and in the course of his job he often needs to jigger with various stage components while shows are in progress. As you can imagine, the lighting situation is far from ideal, so he asked [miceuz] to build him an adjustable lighting solution for his tool box.

The circuit itself is relatively straightforward, using an ATMega88 to provide the PWM required for dimming and color control. Input is taken from three different sources, a rotary encoder for color selection, a pot for brightness control, and a button to turn the light strip on and off.

[miceuz] says that while project came together pretty easily, it still presented some issues along the way which provide some useful design reminders for beginners (and some veterans) alike.

First and foremost: debounce, debounce, debounce. [miceuz] forgot this mantra and made a mad dash to add capacitors to his design after etching the PCB to ensure that his inputs were not bouncing all over the place. He also noted that one should always be sure to read the ADCL before the ADCH register when decoding ADC data. His final observation is that using thick traces is the best policy whenever possible – he ran into a lot of issues with traces detaching during assembly, which he had to rework with wire and solder.

In the end, his friend was happy with the result, and [miceuz] is a better hacker for having worked through his issues. What sorts of important/useful lessons have you learned through the course of your projects? Be sure to share them with us in the comments.


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