Mangling Images With Audio Effects

Ever wonder what those snapshots you took of your trip to Paris would look like if you ran them through a Proco RAT or a Boss Overdrive? How about a BF-3 flanger? [Robert Foss] wrote in with this nifty little script (GitHub) that processes images as if they were audio files so that you can try it out without investing in a rack of analog pedals. Test your audio/visual DSP intuition and see if you can name the images without looking at the effects.

If you know your Linux command-line utilities, there’s really not much to it — scroll down to the very bottom of the script to see how it’s done. ffmpeg converts the images to YUV format, which works much better than RGB for audio processing, and then sox adds the audio effects. Another trip through ffmpeg gets you back to an image or video.

OK, it’s cheating because it’s applying the audio effects inside the computer, but nothing’s stopping you from actually taking the audio out and running it through that dusty Small Stone. Of course, once you’ve got audio outside of the computer, the world is your oyster. Relive the glorious 70’s when video artists made works using souped-up audio synthesizers. If you haven’t seen the Sandin Image Processor or the Scanimate in action, you’ve got some YouTubing to do.

Glitchy Synthesizer Meets Honeycomb LED Matrix

Don’t watch [Jason Hotchkiss]’s video if flashing lights or bleepy-bloopy synthesizer noises give you seizures. Do watch, however, if you’re interested in a big honeycomb-shaped LED matrix being driven at audio frequencies through a dedicated square-wave synthesizer that’s built in.

The LED panel in question is housed in a snazzy laser-cut, honeycomb-shaped bezel: a nice change from the standard square in our opinion. The lights are 1/2 watt (whoa!) whites, and the rows and columns are driven by transistor drivers that are in turn controlled by shift registers. We’re not entirely sure how the matrix is driven — we’d love to see a circuit diagram — but it looks like it’s some kind of strange, non-scanning mode where all of the column and row drives are on at once. Whatever, it’s art.

And it’s driven by logic chips making audio-frequency square waves. Two of these are fed into an LFSR and into an R-2R DAC and then into the shift registers. The output is chaos, but the audio and the visuals do seem to influence each other. It’s an audio-visual embodiment of some of my wildest Logic Noise fantasies. Pretty cool. Enjoy the video.

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Bitbanging VGA Fits In under 1 kB

Don’t throw those old VGA monitors away, turn them into works of art with [danjovic] and VGA Blinking Lights. This circuit uses a PIC16F688 to generate VGA video. Not just a random spray of monochrome dots either. VGA Blinking Lights puts up an ever-changing display of 48 colored squares.

blink-thumbOriginally created for the square inch contest, VGA Blinking Lights could hide behind a quarter. [Danjovic] dusted his project off and entered it in The 1 kB Challenge. The code is written in PIC assembly. The final hex used to generate the squares clocks in at 471 words. Since the PIC uses a 14 bit word, that’s just over 824 bytes. Plenty of space for feature creep!

Video is generated with a twist on the R2R DAC. [Danjovic] tweaked the resistor values a bit to obtain the correct voltage levels for the VGA standard. The color of the squares themselves are random, generated using a Galois Linear Feedback Shift Register (LFSR).

With only a handful of components, and a BOM cost under $5, this would be a fun evening project for any hardware hacker.

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If you have a cool project in mind, there is still plenty of time to enter the 1 kB Challenge! Deadline is January 5, so check it out and fire up your assemblers!

Build the Simplest Bipolar Power Supply

How many integrated circuits do you need to build up a power supply that’ll convert mains AC into a stable DC voltage? Would you believe, none? We just watched this video by [The Current Source] (embedded below), where he builds exactly that. If you’re in the mood for a very well done review of diode bridges as well as half- and full-wave rectifiers, you should check it out.

First off, [TCS] goes through the basics of rectification, and demonstrates very nicely on the oscilloscope how increasing capacitance on the output smooths out the ripple. (Hint: more is better.) And then it’s off to build. The end result is a very simple unregulated power supply — just a diode bridge with some capacitors on the output — but by using really big capacitors he gets down into the few-millivolt range for ripple into a constant load.

The output voltage of this circuit will depend on the average current drawn, but for basically static loads this circuit should work well enough, and the simplicity of just tossing gigantic capacitors at the problem is alluring. (We would toss in a linear regulator somewhere.)

Quibbling over circuit designs isn’t why you’re watching this video, though. It’s because you want to learn something. Check out the rest of his videos as well. [TCS] has only been at it a little while, but it looks like this is going to be a channel to watch.

Don’t Make Your Battlebot Out Of A Pumpkin

It’s that time of year again. The nights are getting longer and the leaves are turning. The crisp fall air makes one’s thoughts turn to BattleBots: pumpkin-skinned BattleBots.

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Kids these days can’t even draw without a computer

If you’re asking yourself, “could a laser-cut plywood bot, sheathed in a pumpkin, stand up against an all-metal monster”, you haven’t seen BattleBots before. Besides the hilarious footage (see video embedded below), a lot of the build is documented, from making a CAD model of a pumpkin to laser-cutting the frame, to “testing” the bot just minutes before the competition. (That has to be a good idea!)

The footage of the pumpkinbot’s rival, Chomp, is equally cool. We love that the hammer weapon is accelerated so quickly that Chomp actually lifts in the air, just as Newton would have predicted. We’re not sure if the fire weapon is good for anything but show, and facing plywood pumpkinbots, but we love the effect.

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RPi Show and Tell Saturday and NYC Meetup on Monday

Join Hackaday for the vanguard of cool emerging technologies next week at our meetup in New York.

Like all our meetups, we’ve gathered some of the neatest technologists to spill the beans on what they’re doing and how they’re doing it. Madison Maxey, founder of Loomia and designer of soft, blinky circuits will be there. Dr. Ellen Jorgensen, co-founder and executive director of Genspace, the citizen science biotech ‘hackerspace’ in the heart of New York will be there too. Kari Love & Matthew Borgatti of Super-Releaser, most famous for their super cute pneumatic soft robots will also be there. It’s still up in the air if we’ll be racing these robots. Of course there will also be opportunities for you to present a lightning talk at the meetup.

enlightenpiThe meetup will be at Pivotal Labs, 625 Ave of the Americas, on Monday, October 24 starting at 6:30 PM. An RSVP is required, so if you’re coming head on over to the Meetup page.

Live Video Show and Tell on Saturday

This Saturday join us online for a special show and tell all about Raspberry Pi projects from 7-8p EDT (UTC-4). Hosted by Limor Fried of Adafruit and Sophi Kravitz from Hackaday. This live show is hosted on our YouTube channel and will feature projects from our giant collection of Raspberry Pi projects on Hackaday.io and entries in the Enlightened Raspberry Pi contest.

A lot of people have already signed up for the Show and Tell but we do still have some time left for your project. Email sophi@hackaday.com to get on the list.

Retrotechtacular: Piano Rolls, Made By Apple ][

Piano rolls are the world’s longest-lasting recording medium, and its first digital one. They were mass-produced from 1896 to 2008, and you can still get some made today, although they’re a specialty item. The technology behind them, both on the player and the recorder side, is simply wonderful.

[lwalkera] sent us in this marvelous video (embedded below) that provides a late-80s peek inside the works of QRS Records, and the presenter seems to be loving every minute of it.

Player pianos are cool enough, with their “draw bar” pulling air through the holes in the paper roll as it goes by, and pneumatically activating the keys. But did you ever think of how the rolls are made?

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