Analog Stylophone

September 23, 2010 by Mike Szczys 7 Comments

[Doug Jackson] just finished building an analog Stylophone. We’ve seen this instrument a few times before, most recently with an Arduino-based controller, but this one makes use of 555-timer, resistors, and potentiometers to generate the waveform for each note. If you’ve got the copper-clad and the means to etch the board everything else should be pretty easy to come by. We did note that since this is a single-sided board you’ll be soldering on the same side as the components, which can get a bit hairy but manageable. We just wish that [Doug] has posted a demonstration video so we could hear what this sounds like. But it can’t be too much different from that electronic vuvuzela that used a 555 timer as well.

Codec2: GNU Low-bitrate Speech Codec

September 23, 2010 by Mike Szczys 11 Comments

Low bandwidth speech compression is a desirable concept for amateur radio enthusiasts. Unfortunately there isn’t a great open-source option out there, but that’s changing with the low-bitrate speech compression package called Codec2. It manages to transmit and decode at 2550 bits per second with results comparable to proprietary solutions like MELP and very near the initial goal of 2400 bit/s. [David Rowe], who spearheads the project, has been simulating communications using a Linux box and has posted audio snippets at the first link above for comparison. They’re looking for feedback and testing so if you interested give them a helping hand.

[Thanks Robomo]

2-bit Paper Processor Teaches How They Work

September 23, 2010 by Mike Szczys 17 Comments

Take a few minutes out of your day, grab your scissors, and learn how a simple processor works. [Saito Yutaka] put together an exercise to teach processor operations with paper. After downloading the PDF you can cut out the Address and Data pointer as well as two-bit data tokens for each. The processor has three instruction sets; Increment register by one, Jump if not over flow, and Halt wait for reset.

Once you’ve got your cutouts you can follow along as the program is executed. The INC operation is run, with the JNO used to loop the program. Once the register has reached an overflow the overflow counter halts the program.

One word of warning, we think there’s a typo in one of the captions. Once the program starts running and gets to address 01(2) the caption still reads 00(2) for both address and data. As long as you compare the values in the picture along the way you should have no problem getting through execution. which has now been fixed.

A Fantastic Collection Of Slapped Together Bots

September 23, 2010 by Caleb Kraft 7 Comments

[David Williamson] has put together some pretty amazing little robots from bits of stuff he laying around the house. What initially caught our attention was this drawing robot over at HackedGadgets. We were impressed by the construction, as it looks like almost all of it was scrap. Upon clicking through the link we found a small collection that kept as amused for quite a while. Each one has some aspect that is surprising in its use of mundane materials. Need an omniwheel? Why not use plastic beads. Want a rail from which a robot can hang and drive? why not use drinking straws. Many of them may not have much for a brain, but the construction of the mechanisms is usually pretty interesting alone. You can see clips of some of his creations in the video after the break.

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Build A Tetrahedral Ambisonic Microphone

September 22, 2010 by Mike Szczys 27 Comments

[Dan Hemingson’s] been refining a design for building a tetrahedral ambisonic recording system. This is a set of four microphones used to record audio that can later be mixed down for a three-dimensional listening experience. His goal is an easy and inexpensive build while maintaining the highest fidelity standards possible. Lucky for us he’s made a set of extremely detailed build instructions you can use to make your own. In addition to the mounting bracket seen above he has also developed a pre-amp module that connects to the four mics; it’s part of the build instructions with schematic and board layout files available as well.

[Thanks Isaac]

Input Device Using LED And Four Photoresistors

September 22, 2010 by Mike Szczys 38 Comments

[Julien] built an input device that uses reflected light detected by some photoresistors. Placing your hand above the device will reflect light from the LED back down onto the cadmium-sulfide sensors. The resistance of those sensors is read by four ADC pins on a Teensy microcontroller and translated to mouse movements. In the video after the break you can see that this works rather well in controlling the cursor. The source code is available on pastebin but we’re also going to host the code for posterity.

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Darbuka Band

September 22, 2010 by Mike Szczys 13 Comments

This robotic band has just the right amount of drums. [Liat] and her colleagues fit a group of Darbuka drums with a pair of servo-driven mallets. We’re quite surprised that the servo motors achieve such a successful strike and rebound without dampening the vibrations of the drum head. This is more often accomplished with solenoids because of their quick response and relative strength.

You can listen to a performance of this work-in-progress in the video after the break or make plans to see it live. The installment was built for the Bat-Yam international biennale of landscape urbanism. It will be attached to, and powered by alternative energy producers like solar cells and wind turbines. Continue reading “Darbuka Band” →