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.

Dartboard Watches Your Throw; Catches Perfect Bullseyes

Some people really put a lot of effort into rigging the system. Why spend years practicing a skill and honing your technique to hit a perfect bullseye in darts when you can spend the time building an incredibly complicated auto-bullseye dartboard that’ll do it for you?

In fairness, what [Mark Rober] started three years ago seemed like a pretty simple task. He wanted to build a rig to move the dartboard’s bullseye to meet the predicted impact of any throw. Seems simple, but it turns out to be rather difficult, especially when you choose to roll your own motion capture system.

That system, built around the Nvidia Jetson TX1, never quite gelled, a fact which unfortunately burned through the first two years of the project. [Mark] eventually turned to the not inexpensive Vicon Vantage motion capture system with six IR cameras. A retroreflector on the non-regulation dart is tracked by the system and the resulting XY data is fed into MATLAB to calculate the parabolic path of the dart. An XY-gantry using six steppers quickly shifts the board so the bullseye is in the right place to catch the incoming dart.

It’s a huge amount of work and a lot of money to spend, but the group down at the local bar seemed to enjoy it. We wonder if it can be simplified, though. Perhaps tracking just the thrower’s motions with an IMU-based motion capture system and extrapolating the impact point would work.

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Light Replaces Electrons for Giant Vector-Graphics Asteroids Game

For all its simplicity, the arcade classic Asteroids was engaging in the extreme, with the ping of the laser, the rumble of the rocket, the crash of crumbling space rocks, and that crazy warble when the damn flying saucers made an appearance. Atari estimates that the game has earned operators in excess of $500 million since it was released in 1979. That’s two billion quarters, and we’ll guess a fair percentage of those coins came from the pockets of Hackaday’s readers and staff alike.

One iconic part of Asteroids was the vector display. Each item on the field was drawn as a unit by the CRT’s electron beam dancing across the phosphor rather than raster-scanned like TV was at the time. The simple graphics were actually pretty hard to create, and with that in mind, [standupmaths] decided to take a close look at the vector display of Asteroids and try to recreate it using a laser.

To be fair, [Seb Lee-Delisle] does all the heavy lifting here, with [standupmaths] providing context on the history and mathematics of the original vector display. [Seb] is a digital artist by trade, and has at the ready a 4-watt RGB laser projector for light shows and displays. Using the laser as a replacement for the CRT’s electron beam, [Seb] was able to code a reasonably playable vector-graphic version of Asteroids on a large projections screen. Even the audio is faithful to the original. The real treat comes when the laser is slowed and a little smoke added to show us how each item is traced out in order.

All [Seb]’s code is posted on GitHub, so if you have a laser projector handy, by all means go for it. Or just whip up a custom vector display for your own tabletop version of Asteroids.

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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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Own the Night with this Open Source Night Vision Monocular

If you’ve always wanted to see in the dark but haven’t been able to score those perfect Soviet-era military surplus night vision goggles, you may be in luck. Now there’s an open-source night vision monocular that you can build to keep tabs on the nighttime goings-on in your yard.

Where this project stands out is not so much the electronics — it’s really just a simple CCD camera module with the IR pass filter removed, an LCD screen to display the image, and a big fat IR LED to throw some light around. [MattGyver92] seemed to put most of his effort into designing a great case for the monocular, at the price of 25 hours of 3D printer time. The main body of the case is nicely contoured, the eyepiece has a comfortable eyecup printed in NinjaFlex, and the camera is mounted on a ball-and-socket gimbal to allow fine off-axis angle adjustments. That comes in handy to eliminate parallax errors while using the monocular for nighttime walks with both eyes open. One quibble: the faux mil-surp look is achieved with a green filter over the TFT LCD panel. We wonder if somehow eliminating the red and blue channels from the camera might not have been slightly more elegant.

Overall, though, we like the way this project came out, and we also like the way [MattGyver92] bucked the Fusion 360 trend and used SketchUp to design the case. But if walking around at night with a monocular at your face isn’t appealing, you can always try biohacking yourself to achieve night vision.

Arduino Video isn’t Quite 4K

Video resolution is always on the rise. The days of 640×480 video have given way to 720, 1080, and even 4K resolutions. There’s no end in sight. However, you need a lot of horsepower to process that many pixels. What if you have a small robot powered by a microcontroller (perhaps an Arduino) and you want it to have vision? You can’t realistically process HD video, or even low-grade video with a small processor. CORTEX systems has an open source solution: a 7 pixel camera with an I2C interface.

The files for SNAIL Vision include a bill of materials and the PCB layout. There’s software for the Vishay sensors used and provisions for mounting a lens holder to the PCB using glue. The design is fairly simple. In addition to the array of sensors, there’s an I2C multiplexer which also acts as a level shifter and a handful of resistors and connectors.

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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!