Giving A Crank Flashlight A Super Capacitor Overhaul

June 21, 2013 by Mike Szczys 25 Comments

crank-flashlight-supercap-overhaul

[Caleb] was given a tiny LED flashlight which has a crank used to charge it. Unfortunately it wasn’t holding a charge, and constant cranking didn’t work very well either. He cracked it open to find a single lithium button cell. Instead of using a drop-in replacement he soldered in his own super capacitor.

The stock device is remarkably simple. It uses a standard DC motor as the generator. It’s connected to the crank using a set of gears, with the two red wires seen above connecting it to the control board. Four diodes make up a bridge rectified and apparently feed directly into the battery. No wonder that cell went kaput!

But this orientation isn’t bad for using capacitors. They can be charged directly and the switch which attaches the LEDs to voltage doesn’t interfere with their operation. The last problem was making room for them in the case. [Caleb] considered a few different approaches, but ended up just heating the plastic enclosure until it could be deformed to make room for the additional parts.

Arduino Particle Light Box Generates Animations From Sound

May 28, 2013 by Mike Szczys 14 Comments

arduino-particle-display

Simple tools used well can produce fantastic results. The hardware which [Gilad] uses in this project is the definition of common. We’d bet you have most if not all of them on hand right now. But the end product is a light box which seems to dance and twirl with every sound in the room. You should go watch the demo video before reading the bill of materials so that the simplicity doesn’t spoil it for you.

A wooden craft box serves as the enclosure. Inside you’ll find an Arduino board, microphone, and an 8×8 RGB module. The front cover of the project box diffuses the light using a sheet of tracing paper on a frame of foam board. It’s the code that brings everything together. He wrote his own particle system library to generate interesting animations.

If you don’t have a project box on hand this might work with an extra-deep picture frame.
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WS2811 Can Be Addressed At 800kHz Using A 8MHz Clock

May 27, 2013 by Mike Szczys 35 Comments

ws2811-running-at-8mhz

Timing is everything and that’s why most communication protocols require a very accurate clock source. The WS2811 LED strip controllers are no different. But [Danny] figured out a way to drive them reliably with an 8MHz clock source.

The WS2811 has become one of the most popular controllers for RGB pixels and strips alike. We’ve seen several hacks used to address them, including the 16MHz AVR technique that inspired [Danny] to take on this project. He planned to use that library but the 25-day shipping time for a 16MHz crystal drove home to invent a way to use the internal oscillator instead.

The gist of the hack is that he wrote assembly code to handle pairs of binary bit values. With a code block for each of the four possible combinations in hand he had to find a way to craft the conditional jumps to preserve accurate timing. After hitting the wall trying to solve this puzzle by hand he wrote a C++ program to solve it for home. The proof is in this video which shows one chip driving multiple Larson scanners on a single strip.

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Update: Live Video Played On LED Strip Display

May 26, 2013 by Mike Szczys 11 Comments

update-live-video-on-led-strip-display

[Paul] took this LED display along with him to Maker Faire. To give it some interactivity he figured out a way to make it play live video. It is also activated using some stomp actuators built from piezo speaker elements and rubber floor mats.

This moves his original project in new directions. Back in February he was showing off the RGB LED strip display. He had it playing video but that was all dependent on using previously processed files. This upgrade uses a BeagleBone Black (the newest rendition of the ARM-based development board). [Paul] had tried using a Raspberry Pi board but had trouble with the webcam (mounted above the LED display) dropping frames. With the new board he is able to use the Video4Linux API to capture 30 frames per second and push them out to the display.

So far he’s had five out of the 1920 LEDs die on him. This shows off a couple of good things about using strips like this. A dead pixel doesn’t affect its neighbors. And replacement is as easy as cutting the ribbon on either side of the bad component, then soldering a new segment in place.

LED Etch-a-Sketch Built Without A Microcontroller

May 23, 2013 by Mike Szczys 21 Comments

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This project is a wonderful example of what can be accomplished with a rather complicated logic circuit. It’s an Etch-a-Sketch made from a 16×16 LED grid. That in itself is only somewhat interesting. But when hearing about the features and that it is driven by logic chips we were unable to dream up how it was designed. There’s no schematic but the video commentary explains all.

The thing that confused us the most is that the cursor is shining brighter than the rest of the pixels. This is done with two different 555 times and a duty cycle trick. When you turn the trimpots the cursor position is tracked by some decade counters. Pixels in your path are written to a RAM chip which acts as the frame buffer. And there’s even a level conversion hack that let’s the display run at 15v to achieve the desired brightness. Top notch!
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Adding LEDs To An Engagement Ring

May 20, 2013 by Brian Benchoff 64 Comments

ring

Once upon a time, a nerd met a girl. Things happen as they do, and eventually [Ben] wanted to create the be-all, end-all engagement ring. (here’s a cache) It’s a simple titanium affair with 23 stones around the perimeter. What makes this ring so cool, though, is that it lights up whenever [Ben] and his girl are holding hands.

The metalworking portion of the build was about as easy as you would expect machining titanium to be. After the ring was cut off its bar stock, [Ben] brought it over to a mill where 23 holes for each of the stones were drilled. The stones were affixed to the ring with jewelers epoxy and the entire ring was buffed to an amazing shine.

The electronics are where this project really shines. Putting a battery of capacitor inside a ring is nigh impossible, so [Ben] decided to power the LEDs with an inductive charging circuit. A coil of wire wound around kapton tape serves as the inductor and a small SMD capacitor powers three very bright and very tiny LEDs.

The inductive charging unit itself is a masterpiece of hackery; [Ben] wanted the ring to light up whenever he and his ladyfriend were holding hands. To do this, [Ben]’s inductive charger is also a wearable device: a large coil of wire is the charger’s transformer and was would to fit around [Ben]’s wrist. The entire charging circuit can be easily hidden under a jacket sleeve, making for a nearly magical light-up ring.

An awesome piece of work, and one of the best jewelry builds we’ve seen in a long time. You can see the inductive coupling and shining LEDs in the video below.

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North Street Labs Try To Spice Up A Game Of Tic-Tac-Toe

May 18, 2013 by Mike Szczys 4 Comments

tic-tac-toe-stomp-box

The team at North Street Labs really went all out with this Tic-Tack-Toe stomp box. At its most basic it’s a blinky version of the simple two-player game. But there’s always some added appeal when you make large manifestations of normally small items; the 10x Arduino is a good example of this.

The project is NSL’s qualifying entry for this year’s Red Bull Creation Contest (has it already been a year since the last contest?). A special Arduino shield was produced once again, this time it features hardware necessary to control LED strips… a lot of them. That led to the creation of this box, which houses a ton of strip sections inside to light the grid based on tapping one of the red buttons with your foot. We’d image the game would be seldom used at your hackerspace, but they take it to show off at the local children’s museum and it’s a huge hit with the kids!