Collection Of Nixie Bar Graphs Bump To The Beat

November 5, 2012 by Mike Szczys 10 Comments

This VU meter uses Nixie tubes as the display. There are a total of fourteen IN-13 bar graph tubes that map out the audio spectrum. The build uses purely hardware for the display; no microcontroller processing, or dedicated VU-meter chips were used.

Input begins with a dual Op-Amp along with a pair of potentiometers which allow the left and right channels to be balanced. Both channels are then each split into seven signals, which explains the layout of tubes seen above. Each signal is then fed through a voltage divider to envelope the output between 0V and 6V. There is also a low-pass filter to handle sudden volume spikes which don’t work well with the nixies. But as shown in the video after the break, all that work has paid off. Thr clip gives us a look at the green protoboards which host all of this filtering hardware. You’ll want to turn the volume down for the first couple of demonstrations which use a sweep to test the system.

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[Lou’s] Haircut Really Sucks

November 5, 2012 by Mike Szczys 23 Comments

Ah yes, at some point a brilliant inventor combined the electric trimmer with a vacuum cleaner and the art of cutting hair was never the same again. [Lou] is showing us how to give a haircut that really sucks up the waste. And he did it using rubbish he had lying around.

Most people will recognize this as a DIY version of the Flowbee. Not surprisingly, you can still buy one of those if you want, but [Lou] is looking for a vacuum cutter for trimming his dog’s hair so he’s not about to shell out cash for it. He already has the trimmer, and just needed a way to attach the vacuum hose to it. In the image above you can see the grey crevice attachment for his vacuum. He taped it onto the trimmers, then cut a plastic soda bottle to use as a hood near the business end of the trimmer. It’s all wrapped in packing tape to hold everything in place and seal around the joints. You can see it in action in the clip after the break.

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Beginner Project: Color Sensing With RGB LEDs And A Photocell

November 5, 2012 by Caleb Kraft 16 Comments

I’ve seen the concept art for “real world eyedroppers” several times. I haven’t noticed any of the products come to market though. It isn’t the technology stoping them, color sampling can be done a million ways. I picked one of the easiest ways and tossed something together pretty quickly.

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LED Fun And Light Painting With The PyMCU

November 5, 2012 by Jeremy Cook 2 Comments

Recently [Richard] at [pyMCU] was nice enough to send me one of their units to try out. As featured here before, this little board allows you to control physical things using your computer and the Python programming language. After evaluating it and making a LED blink, there were a couple other LED projects I wanted to try.

The first idea was to make a LED chaser. This was quite simple, using a little code and plugging in a few LEDs. From this, since you can make the LEDs chase each other, then in the right sequence it should be able to be used to display images using long-exposure photography. Be sure to check out the video after the break of this 10 LED chaser/light bar being assembled.

The results of this LED light bar experiment were really cool, writing some simple text and image with 10 LEDs. Considering the low component count, this is one of the simplest light bar builds that we’ve seen. Programming was simple as well, since the computer using Python does all the processing of the drawing as well as physically turning the LEDs on and off. Of course this setup isn’t without its limitations, having to be connected to a computer being the most obvious. Continue reading “LED Fun And Light Painting With The PyMCU” →

MR-808 Is A Mechanical Version Of The Most Famous Drum Machine

November 5, 2012 by Brian Benchoff 27 Comments

Anyone who has listened to any music from the 80s has heard the percussive effects of the infamous TR-808 drum machine. To the modern ear, it sounds like an antique. Being the most popular drum machine of all time means it must have some redeeming qualities, right?

[Moritz Simon Geist] decided he wanted nothing to do with the wimpy computer-based emulations of a TR-808. Instead, he chose a more mechanical version that puts robots inside a gigantic 808 enclosure to play snares, high hats, cowbells, and drums in time with any MIDI drum track.

[Moritz] calls his build the MR-808 and puts a real-life bass drum, snares, hats, toms, claps, and a ride into a 3.3 x 1.7 meter ( 10.8 x 5.5 foot) case. The sound triggers are handled by Max/Msp communicating with a pair of Arduinos to handle the solenoids and light effects. You can read more about the hardware setup in [Moritz]’ behind the scenes look.

After the break you can see the MR-808 in action, both alone and by providing the percussion for [Moritz]’ band. A very cool build that now cries out for an Arduinofied bassist placed into an overgrown TB-303 enclosure.

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Skittles Sorting Machine Sorts Skittles, Keeps The Band Happy

November 5, 2012 by Brian Benchoff 25 Comments

In 1982, Van Halen had the biggest stage show around. Their rider – a document going over the requirements for the show – reflects this. In the middle of the requirements for the lighting and sound rigs, Van Halen placed a rather odd request; one (1) bowl of M&M, (ABSOLUTELY NO BROWN ONES). The theory being if the request for no brown M&Ms wasn’t followed, the lighting and sound rigs probably weren’t up to spec either.

It’s not M&Ms this time (they wouldn’t fit in the machine), but [egenriether] came up with a seriously clever solution for sorting Skittles by color. Why? We have no idea, other than, ‘just because.’

The build details are a little scant, but we know [egenriether] used a BASIC Stamp 2 for the electronics portion of the build. To sort the Skittles by color, a TAOS RGB color sensor reads the red, green, and blue values for each Skittle and actuates a servo that guides each piece of candy into its respective bowl.

It’s a very, very cool, if completely useless build. Still, we’re thinking it could be put to use if [egenriether] is ever backstage setting up before the band arrives.

Videos after the break. Thanks [Andrew] for sending this one in.

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[Jeri] Shows Off A Delta Sigma ADC

November 5, 2012 by Brian Benchoff 56 Comments

[Jeri] has had a bear of a time moving up to Valve Software, but electron microscope is safely in her garage (!) and her electronics lab is slowly taking shape. Since she can’t bring out the real-life gravity gun she’s working on, she decided to show off a one-bit ADC that uses just a flip-flop to sample an analog waveform into digital data.

By toggling the clock input of a 74xx74 (or any flip-flop, really) and feeding the complimentary output to back into the data input, [Jeri] can get an output that is a 50% duty cycle feeding into the input of the chip. Adding an audio input to this data input with 10k pot to this feedback loop will cause the duty cycle to change in relation to the analog input, making a one-bit ADC.

As with any electronic shortcut, there are a few drawbacks: the clock cycle feeding into the flip-flop has to be pretty fast; at least a few dozen kilohertz if you’re sampling audio. Still, if you don’t have a free ADC pin, or you’d just like to build a bitcrushing guitar pedal, it’s a very simple (and cheap) way to get analog into a digital micro.

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