Day: November 5, 2012

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

November 5, 2012 by 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 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 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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Thinking Cap Is Also Party Hat

November 5, 2012 by 10 Comments

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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