Fully-functional Oscilloscope on a PIC

When troubleshooting circuits it’s handy to have an oscilloscope around, but often we aren’t in a lab setting with all of our fancy, expensive tools at our disposal. Luckily the price of some basic oscilloscopes has dropped considerably in the past several years, but if you want to roll out your own solution to the “portable oscilloscope” problem the electrical engineering students at Cornell produced an oscilloscope that only needs a few knobs, a PIC, and a small TV.

[Junpeng] and [Kevin] are taking their design class, and built this prototype to be inexpensive and portable while still maintaining a high sample rate and preserving all of the core functions of a traditional oscilloscope. The scope can function anywhere under 100 kHz, and outputs NTSC at 30 frames per second. The user can control the ground level, the voltage and time scales, and a trigger. The oscilloscope has one channel, but this could be expanded easily enough if it isn’t sufficient for a real field application.

All in all, this is a great demonstration of what you can accomplish with a microcontroller and (almost) an engineering degree. To that end, the students go into an incredible amount of detail about how the oscilloscope works since this is a design class. About twice a year we see a lot of these projects popping up, and it’s always interesting to see the new challenges facing students in these classes.

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LEGO Looper Makes Modular Music

This LEGO synth made by [Rare Beasts] had us grinning from ear to ear.

It combines elements from LEGO Mindstorms with regular blocks in order to make music with color. A different music sample is assigned to each of five colors: red, blue, green, yellow, and white. The blocks are attached to spokes coming off of a wheel made with NXT an EV3. As the wheel turns, the blocks pass in front of a fixed color sensor that reads the color and plays the corresponding sample. The samples are different lengths, so changing the speed of the wheel makes for some interesting musical effects.

As you’ll see in the short video after the break, [Rare Beasts] starts the wheel moving slowly to demonstrate the system. Since the whole thing is made of LEGO, the blocks are totally modular. Removing a few of them here and there inserts rests into the music, which makes the result that much more complex.

LEGO is quite versatile, and that extends beyond playtime. It can be used to automate laboratory tasks, braid rope, or even simulate a nuclear reactor. What amazing creations have you made with it? Let us know in the comments.

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Piana – Musical Synthesis For The Raspberry Pi

For the last 15 years or so, software synths have slowly yet surely replaced those beatboxes, drum machines, and true synthesizers. It’s a loss for old hardware aficionados, but at least everyone with a MacBook is now a musician, amiright?

The Raspberry Pi and Pi2 already have more processing power than a desktop from ’99, so it’s no surprise that all of those classic synths, from a Moog. Yamaha DX, Casio CZ, Linn drum machine, Fairlight, and a mellotron, can all be stuffed into a Pi thanks to the work of [Phil Atkin] and his Raspberry Pi synthesizer.

[Phil]’s efforts to bring audio synthesis to the Pi fall under three techniques: subtractive synthesis, phase distortion synthesis, and sample-based synthesis, something that’s found in everything from Akai MPCs, MacBooks, and that one episode of The Cosby Show. [Phil] is combining all of these techniques into a piece of software that’s capable of running seamlessly on the Pi, giving anyone with a $35 computer a tool that would have been worth several thousand dollars in 1985.

The project is pretty far along, but the recent release of the Raspberry Pi 2 has thrown [Phil] for a loop. On one hand, the Pi 2 is much more capable than the original Pi in terms of hardware, and this lends itself to more sounds and a better GUI. On the other hand, there are millions of original Pi 1s out there that still make for exceptional synthesizers. Either way, [Phil]’s work is a great example of how far you can push the Pi with audio work.

Thanks [Wybren] for the tip. Videos below.

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Darth Vader Magic 8 Ball

Imagine that your wife likes Darth Vader and wants help making important life choices. (Who doesn’t?) [bithead942] solves both problems in one project by gutting a Lego clock and making a talking animatronic Darth Vader 8-Ball-style oracle. Now his wife can simply press Darth’s head and her decision-making is handled by the Dark Side of the Force.

You can see the result in the video below the break.

The internals consist mainly of an Arduino Nano, a WTV020SD WAV playback chip, and some swanky servos. [bithead942] took a Dremel to the existing clock interior and found a way to make it all fit. The cloak helped, and the speaker was a good fit for the previous clock’s display.

Then he used IMDB and combed through the Star Wars movies to find Darth Vader quotes that kinda sound like the 8-Ball’s answers. As [bithead942] mentions Darth Vader doesn’t really dwell much on the positive, so finding instances where he says “yes” was hard work. This is in contrast to the original 8 Ball which has a brighter outlook than a cheerleader on Prozac, but there’s a reason they call it the Dark Side.

We really like the way the waist and arm servos work together to bring Darth to life. The added oak base with pull-out instruction card not only makes Darth look fancy, but prevents him from falling over when he leans forward to talk. All in all, a really nice build and well written-up with difficulties and their solutions.

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Draw your own vinyl beats


The Dyskograf lets you make music with a magic marker. The musical installation looks much like a turntable for playing vinyl records. But instead of a spiraling groove containing the sounds, this uses marks on a paper disk to play sound samples.

You can see the light outline of several tracks on the paper disc shown above. By adding black marks the optical input of the Dyskograf knows when to start and end each sound. This is best illustrated in the video demonstration after the break.

The marker-based setup makes a lot of sense, and we think it would be perfect if the disc was a dry-erase board. It certainly makes it a lot easier to lay down new beats than this other optical turntable which required holes to be drilled in a vinyl record to play the sounds. While we’re on the topic you may also find this coin-based turntable sequencer of interest.

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