Soundball Bumps To Your Tunes

August 7, 2013 by 7 Comments

soundball-blinks-to-the-music

Meet soundball, a hobby electronics project when replaces a disco ball with one made of LEDs (translated) going every which way. This image shows the device before being injected into an enclosure. The final offering is a white project box with a hole in the top through which the diffuser covered blinky ball is supported.

The main board hosts a collection of the usual suspects: an ATmega328, an MSGEQ7 equalizer, a couple of TLC5940 LED drivers, and a footprint for a Bluetooth Shield. The equalizer chip provides [Cornelius] the audio analysis used to generate light patterns that go along with the music.  But he can still control the lights manually with a button on the case or by connecting to it via Bluetooth.

Swap out the LED drivers for some solid state relays and you can blink your Christmas lights to the music.

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A Cold Cathode Audio Visualizer

August 7, 2013 by 18 Comments

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Finally, cold cathode lights can be used for much more than illuminating the inside of your computer or making your whip look like it can hover. [James] discovered if he varied the voltage going into the inverter, only a certain amount of the tube would light up. Give a hacker an interesting observation and enough time, and eventually he’ll come up with something really cool. In this case, it’s a cold cathode audio visualizer, powered by fluorescent tubes doing unexpected things.

The build details are a little scant, but we were able to coax an imgur album of [James]’ build. He’s using these 20″ CCFL lights with the stock digital inverters replaced with TDK CCFL inverters.

The digital control of this build is provided by an Arduino Mega and a custom shield. We’re guessing the graphic EQ is provided by an MSGEQ7 chip, and the inverters themselves are powered through the Mega’s PWM pins. It’s a lot like an IN-9 Nixie graphic EQ, only much, much bigger. [James] is planning a larger version of this build, dubbed the Mega speKtrum and we can’t wait to see that build along with a proper writeup.

Taming STM32 Discovery Boards For Regular Use

August 7, 2013 by 6 Comments

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We think [Karl Lunt] has a point when he says that the STM32 Discovery Boards are cool and inexpensive, yet not hobby friendly. But it’s nothing that a little big of creativity can’t solve. Above are pictured three of the hacks he used to tame the Discovery boards.

The first is the addition of a microSD card adapter. He soldered wirewrap wire to each of the contacts on the adapter. He recommends a low iron setting to make sure you don’t melt the plastic adapter housing. He then used double stick foam tape to adhere it to the bottom of the dev board. The other ends of the wire are wrapped around the appropriate pins on the dual-row pin header. Similarly, the UART3 connections are broken out from the pin headers to that white quick connect socket. This lets him access serial data without having to solve the USB issues that were vexing him.

Finally, he made his own daughter board to break out the dual row headers into screw terminals. We’ve been hit with problems interfacing hardware with the board’s native connections — jumpering to IDE cables just never worked reliably. This breakout board not only makes it simple, but organizes the pins into groups based on their alternate functions.

Do you remember seeing the hacksaw version of this Discovery board which gives you two dev boards for the price of one?

A Full-auto Gauss Gun Probably Won’t Hurt Much

August 7, 2013 by 99 Comments

While it may only be able to shoot a few cans right now, we certainly wouldn’t want to be in front of [Jason]’s fully automatic Gauss gun capable of firing 15 steel bolts from its magazine in less than two seconds.

The bolts are fired from the gun with a linear motor. [Jason] is using eight coils along the length of his barrel, each one controlled by an IGBT. These are powered by two 22 Volt 3600mAh LiPo battery packs.

As for the mechanical portion of the build, the bolts fired from this gun are actually 6.5mm nails, cut off and sharpened. These are chambered from a spring-loaded magazine, with each new bolt put into the breech with a small solenoid retracting for an instant. The frame is constructed from a square aluminum tube with additional pieces cut with a hacksaw and bent with an impromptu bench vise brake. If ever there was a person deserving of a bench top shear/brake, [Jason] is the man.

The muzzle velocity of these bolts is about 40 m/s, with a muzzle energy that’s about 3% of a .22 LR round. Not deadly, but more than enough for picking off a few cans and bottles in a garage. You can see the video of this futuristic Gauss machine gun below.

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Retrotechtacular: Singing Bird Automata

August 6, 2013 by 16 Comments

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Our cats were both sleeping near the computer and these videos were driving them nuts. To our ears these birdsongs sound pretty good. They didn’t trick the cats into stalking mode, but they did spark an audible complaint. So the predators aren’t drooling but the mechanical engineers reading this should be. These automata combine the precision of a mechanical clock with a bellows and specialized whistle to recreate birdsong.

You’ve got to hear it for yourself to appreciate the variety produced by the mechanisms. The first video shows off the device seen on the left. This particular model is from the 1890’s and the demo gives a good look at the arms that open and block a passageway to alter the sound. After seeing that link — which was sent in by [Stefan] — we started searching around for more info on the devices. The one pictured to the right turned up. It’s from YouTube user [Singing Bird Boxes] who has many videos showcasing these types of devices. We picked this one because he tried to explain how each part of the mechanism works. These are still being made today, but there’s something magical about seeing one built during the steam age.

We’d like to make Retrotechtacular a weekly feature every Tuesday. Help us out by sending in links to projects that highlight old technology, instructional videos of yore, tours of museums or similar relics.

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Leap Motion Controls Hexapod With Hand Signals

August 6, 2013 by 9 Comments

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Moving your hand makes this hexapod dance like a stringless marionette. Okay, so there’s obviously one string which is actually a wire but you know what we mean. The device on the floor is a Leap Motion sensor which is monitoring [Queron Williams’] hand gestures. This is done using a Processing library which leverages the Leap Motion API.

Right now the hand signals only affect pitch, roll, and yaw of the hexapod’s body. But [Queron] does plan to add support for monitoring both hands to add more control. We look at the demo after the break and think this is getting pretty close to the manipulations shown by [Tom Cruise] in Minority Report. Add Google Glass for a Heads Up Display and you could have auxiliary controls rendered on the periphery.

While you’re looking at [Queron’s] project post click on his ‘hexapod’ tag to catch a glimpse the build process for the robot.

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Avalanche Pulse Generator Design

August 6, 2013 by 25 Comments

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This avalanche pulse generator is a great way to test your mettle as an Electronics Engineer. The challenge is to truly understand how each part of the design works. We certainly got a failing grade when first studying the schematics more than a week ago. But we’re slowly beginning to understand what’s going on under the hood.

The concept of an avalanche transistor is some wicked voodoo from the analog side of the street which leverages a transistor’s breakdown voltage to achieve a predictable result. In laymen’s terms it (mis)uses a transistor to produce a really fast pulse. The write-up linked above references several previous avalanche pulse generator designs, but this one is a bit different in how it produces about 50V from a pair of AAA batteries using a multivibrator circuit.

Even if you have no idea what’s going on here you may be interested in the last few paragraphs where the circuit is measured using a cutting-edge Teledyne LeCroy Wavemaster 820Zi-A. That’s a 20 GHz scope with a 15.3″ screen which you’ll never ever own.