Keyboard Composes Its Own Music

May 1, 2012 by 5 Comments

Summer is right around the corner and all the final projects from electronic design classes are rolling into the tip line. This time, we’ve got [Chaorong] and [Siyu]’s auto-composing keyboard from their time in ECE4760 at Cornell.

The keyboard has two modes: a ‘happy’ mode and a ‘tender’ mode, the difference being the tender mode is slower and sounds a little like a lullaby. After two keys are pressed, the ATMega644 figures out what key it should play in and starts generating a random-ish sounding song using a Markov probability matrix.

There’s a third option for the keyboard as well: play a short melody and the software will loop through a few permutations of the melody. After the break, you can see [Siyu] play Ode to Joy and have the autocomposer improvise around the tune. Very, very nice work and we can’t wait to see more senior design projects hit the tip line.

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RCA Capacitive Electronic Disk

May 1, 2012 by 25 Comments

capacitive video disk

Although not a hack in the sense that it was made by a large corporation, check out this capacitive electronic disk that [danielbpm] wrote in about. Here’s a Wikipedia article about it, as well as a video (which didn’t embed correctly) about how it was made. The disks look like a typical audio record, and it was conceived of in 1964. A prototype was manufactured in 1972.

Unlike the more well-known Laserdisk format, the [Capacitive Electronic disk], or [CED] used an actual stylus to read the disks. Because of this, the [Wikipedia] article astutely points out that both systems were mutually incompatible. Somewhere there might have been a scratched Laserdisk next to the VCR with a sandwich stuffed in it. The computer with a broken coffee holder wouldn’t come for another few years.

Although it may have been a good format in it’s own right, like Betamax or HD-DVD, this system wasn’t destined to become the Blu-Ray player of it’s time.

Electronic Table Top Catapult

April 30, 2012 by 14 Comments

[Unusualtravis] came up with this fairly slick electronic catapult. This easy to construct and moderately cheap rig has an arduino as the brains and controls for 3 servos. One is the release, another controls tension, and the third controls the angle. Both the circuit and the construction are very simple making this a perfect weekend project. He would have preferred it to be a bit smaller, so shoot him your design if you manage to shrink it.

We’ve always been rather fond of catapults of whatever complexity, so feel free to send in any variations you’ve worked on.

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6 Camera Face Scanning Rig

April 30, 2012 by 6 Comments

[Ajeromin] was asked to build something cool for a museum exhibit. He took the challenge, and with his facial capture device, we feel he delivered. The writeup is very short, most of the story is in the annotated images. After deciding he was going to do facial capture and convert it to 3d, he had to start planning. There are many ways to do this, but usually the person having their face captured isn’t an excited child at a museum. The presented some unique challenges in that he knew he would have to capture all the images at once, and quickly too. To do this, he lit the entire rig very well to reduce the amount of noise in the pictures and wired all 6 cameras up to snap at the same moment. He even encapsulated the circuit in a glass jar just so the kids could see more of the parts.

The next logical step would be to attach this to a 3d printer and let people buy 3d printed models of their face. The quality is certainly good enough as he shows in one of the final images.

Great job [Ajeromin]

 

Tindie: An Etsy For Electronics

April 30, 2012 by 39 Comments

If you have a finished project you’re now bored with, here’s Tindie. It’s a one-man operation headed b [emile] that hopes to connect makers with people who think DIY projects are really cool and have money.

There are already a few websites that cater to the builder who wants to sell projects: Kickstarter for one, but this is based on the concept of campaigns. Tindie aims to be a techie etsy, according to [emile]’s market research post on reddit;  a places for makers with a soldering iron to sell stuff, but who are baffled by the concept of knitting.

Right now there’s nothing to buy on Tindie – [emile] is looking for hackers to sell their projects so the store doesn’t launch with an empty stockroom. If you’ve got an old project sitting on your shelf that you’d like to sell, put it up. [emile] is only taking 5% of the sales – just enough to pay for the hosting. Hopefully it will be popular enough for the eventual Tindie/regretsy blog.

Quick And Easy Wildlife Camera

April 30, 2012 by 9 Comments

This wildlife camera is really easy to put together. You should keep it in mind if you’re ever tying to figure out what’s eating the heads off of all of your tulips. [Revoltlab] put it together, and although there’s one fatal flaw in this particular system, the concept is quite sound.

The build uses a camera, paired with an ultrasonic range finder. When something passes within the pre-set distance for the sensor, a servo motor clicks the shutter button on the camera. It’s all driven by an Arduino and powered from a 9V battery.

If you watch the video after the break you’ll discover the flaw we mentioned. This is a disposable film camera and requires winding between pictures. That hasn’t been implemented yet. But we’ve got an old digital camera with a broken LCD screen which would be perfect for the job. We’d have to do a bit more work to turn the camera on before taking the picture though.

There are a couple of possible upgrades to the idea. [Revoltlab] mentions removing the IR filter from the camera and adding an infrared flash for night-vision shots. But we would also recommend ditching the servo motor for a simple remote shutter solution as a way to avoid scaring the wildlife with the motor noise.

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Inconspicuous Guitar Hack Adds A Lot Of Control To Max/MSP

April 30, 2012 by 4 Comments

[Sam] is working on his Interactive Technology Degree and he made some alterations to this guitar as a class project. It doesn’t look much different, but closer inspection will reveal a handful of extra buttons, and a camera module. He actually added a Wii remote to the guitar which is used to control Max/MSP.

His pinky is pointing at one of the buttons. That one is red and triggers the Bluetooth sync function for the Wii remote. The other four buttons are wired to the up, down, A, and B buttons. In the video after the break [Sam] talks about the Max/MSP front-end which is used to connect the remote to the computer. Once communications are established the accelerometer sensor data is continuously streamed to the software, and the other four buttons are used for controlling the patches.

The camera module that is mounted in the guitar can be used to stream video but it appears to have no effect on the sound. In fact, the live video feed can be mixed with a waveform generation. Sound characteristics like volume affect the cross-fade between the two video signals. [Sam] talks about this feature, but when the playing demo starts about 6:10 into the clip we don’t seen any of the live video on the projection screen.

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