RAM Fiddling Turns VGA Converter Into Video Synth

If you’re interested in circuit bent video but not sure where to start, the excellent guide [LoFi Future] has come up with for modifying the cheap and readily available GBS-8100 VGA to composite converter would be a great first step. While we wouldn’t call it an easy modification, the circuit documentation and demonstration video below go a long way to making it as accessible as possible to new players.

Some soldering will be required…

While other video converters have all-in-one chipsets that are much harder to work with, [LoFi Future] explains that the separate EM636165TS DRAM chip on the GBS-8100 provides an ideal spot to tap in and wreak some technicolor havoc. By mapping out the pins and studying how the video output is corrupted by grounding them out or connecting them to each other, he’s been able to come up with fairly repeatable “recipes” for different effects.

In the most basic form, once you’ve soldered the pins of the DRAM chip up to the plug board interface, you’d technically be done. But [LoFi Future] takes it a step further and pairs the GBS-8100 with a separate composite to VGA converter. This provides some additional effects in the form of feedback loops and hue adjustment, but more practically, allows the device to handle composite on both the input and output. It’s a lot of hardware to cram into the enclosure, but thanks to little touches like the printed panel graphics, the final product does looks very professional.

Aside from the occasional modified NES Zapper, most of the circuit bent hardware we see is of the audio variety. But with projects like this one and the MIDI controlled SNES we covered last year as inspiration, we might see a balancing of the scales. Continue reading “RAM Fiddling Turns VGA Converter Into Video Synth”

Controlling A Broken Super Nintendo With MIDI

A Super Nintendo that has trouble showing sprites doesn’t make for a very good game system. As it turns out, Super Mario World is a lot less fun when the titular hero is invisible. So it’s no surprise that [jwotto] ended up tossing this partially functional SNES into the parts bin a few years back.

But he recently came up with a project that may actually benefit from its unusual graphical issues; turning the glitched console into a circuit bent video synthesizer. The system was already displaying corrupted visuals, so [jwotto] figured he’d just help things along by poking around inside and identifying pins that created interesting visual effects when shorted out.

Installing the new electronics into the SNES.

Once he mapped out the pins, he wired them all up to a transistor switching board that he’d come up with for a previous project. That would let an Arduino short out the pins on command while still keeping the microcontroller relatively isolated from the SNES. Then it was just a matter of writing some code that would fire off the transistors based on MIDI input.

The end result is a SNES that creates visual glitches along with the music, which [jwotto] can hook up to a projector when he does live shows. A particularly neat feature is that each game responds in its own way, so he can swap out the cartridge to show completely different visuals without having to change any of the MIDI sequencing.

A project like this serves as a nice introduction to both circuit bending and MIDI hacking for anyone looking to get their digital feet wet, and should pair nicely with the MIDI Game Boy Advance.

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Hacked Tape Player Makes For A Unique Instrument

[Gijs Gieskes] is certainly no stranger to hacked cassette players, but his latest triumph may well be the most approachable project for anyone looking to explore the world of unorthodox tape unspooling. By attaching a fairly simple add-on PCB to a modern portable cassette player, the user is able to modify the playback speed of the tape at will. The skillful application of such temporal distortions leads to wonderfully abstract results.

The board that [Gijs] has come up with uses four potentiometers and matching push buttons to allow the user to set different playback speeds that they can engage with the push of the button. There’s also a fifth potentiometer to augment the “global” speed as well as an override switch. During playback, these controls can be used to arbitrarily tweak and augment the sound of samples contained on a the looping cassette.

If that’s a little hard to conceptualize, don’t worry. [Gijs] has provided some examples of how the the rapid adjustment of playback speed offered by this “Zachtkind” can add a fascinating level of complexity to sounds and melodies. The assembled player is available for purchase ready to go, but he also provides kits and a detailed installation guide for those who’d rather build it themselves.

Going all the way back to 2005, [Gijs] and his incredible creations have been a staple of Hackaday. From the Arduino video sampler to the array of oddly musical analog clocks, we never cease to be in awe of this exceptionally prolific hacker.

A Baby Named DJ

Some of us are guilty of picking up questionable hardware from garage sales, fleamarkets, and well-meaning relatives. There is a balance between turning down a good investment and hoarding, and if we figure out how to tell the difference you will be the first to know. [Clem Mayer] may start on the side of unwise acquisition, but he pushes a broken fetal detector into the realm of awesome by converting it to an analog synthesizer, born to headline at an Eastern European dance party.

He starts with a basic teardown, and we get to see how old hardware was serviceable with only two standard screws. It is a good thing too, because the nickel-cadmium batteries are older than some of you and they are in need of replacement. New nickel-metal hydride batteries got it up and running but [Clem] does not have a baby bump so its functionality turned to Pink Floyd era synthesizer circuit bending. Circuit bending involves modifying a circuit for sound it was not intended to make.

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Circuit Bending Those Adorable Voices

Leapfrog make some pretty awesome kids electronics. Especially admirable is the low cost, the battery life, and the audio quality of these devices. This circuit bending hack takes advantage of those audio circuits by turning the Alphabet Pal into your lead vocalist. The performance in the demo video begins with some impressive tricks, but just wait for it because by the end the little purple caterpillar proves itself an instrument worthy of a position beside that fancy Eurorack you’ve been assembling.

The image above provides a great look inside the beastie. [Jason Hotchkiss] mentions he’s impressed by the build quality, and we have to agree. Plus, look at all of those inputs — this is begging to leave toyland and join the band. With an intuitive sense that can only be gained through lots of circuit-bending experience, he guessed that the single through-hole resistor on the PCB was used to dial in the clock speed. That made it easy to throw in a trimpot for pitch-bending and he moved on to figure out individual note control.

All of those caterpillar feet are arranged in a keyboard matrix to detect button presses. After pulling out the oscilloscope for a bit of reverse engineering, [Jason] grabbed a PIC microcontroller and added it to the same solder points as the stock ribbon connector. The result is that the buttons on the feet still work, but now the Alphabet Pal also has MIDI control.

Take a look at the writeup for full details, and the video after the break to hear it in action. If you’re a fan of circuit-bent toys, this pretty pink keyboard hack always impressed us, especially the spring reverb that was added!

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Video Mangler For All Your Video Mangling Needs

Back in the ’70s and ’80s, before we had computers that could do this sort of thing, there were fully analog video effects. These effects could posterize or invert the colors of a video signal, but for the best example of what these machines could do just go find some old music videos from Top of The Pops or Beat Club. Stuff gets weird, man. Unfortunately, all those analog broadcasting studios ended up in storage a few years ago, so if you want some sweet analog effects, you’re going to have to build your own. That’s exactly what [Julien]’s Video Mangler does. It rips up NTSC and PAL signals, does some weird crazy effects, and spits it right back out.

The inspiration for this build comes from an old ’80s magazine project called the ‘video palette’ that had a few circuits that blurred the image, turned everything negative, and could, if you were clever enough, become the basis for a chroma key. You can have a lot of fun when you split a video signal into its component parts, but for more lo-finess [Julien] is adding a microcontroller and a 12-bit DAC to generate signals that can be mixed in with the video signals. Yes, all of this can still be made now, even though analog TV died a decade ago.

The current status of this project is a big ‘ol board with lots of obscure chips, and as with everything that can be described as circuit bending, there’s going to be a big panel with lots of dials and switches, probably stuffed into a laser-cut enclosure. There’s a mic input for blurring the TV with audio, and enough video effects to make any grizzled broadcast engineer happy.

Circuit Bent Casio SK-1 Gets An Arduino Brain

The Casio SK-1 keyboard is fairly well-known in the “circuit bending” scene, where its simple internals lend themselves to modifications and tweaks to adjust the device’s output in all sorts of interesting ways. But creating music via circuit bending the SK-1 can be tedious, as it boils down to fiddling with the internals blindly until it sounds cool. [Nick Price] wanted to do something a bit more scientific, and decided to try replacing his SK-1’s ROM with an Arduino so he could take complete control it.

Replacing the ROM chip with header pins.

That’s the idea, anyway. Right now he’s gotten as far as dumping the ROM and getting the Arduino hooked up in place of it. Unfortunately the resulting sound conjures up mental images of a 56K modem being cooked in a microwave. Clearly [Nick] still has some work ahead of him.

For now though, the progress is fascinating enough. He was able to pull the original NEC 23C256 chip out of the keyboard and read its contents using an Arduino and some code he cooked up, and he’s even put the dump online for any other SK-1 hackers out there. He then wrote some new code for the Arduino to spit data from the ROM dump back to the keyboard when requested. In theory, it should sound the same as before, but with the added ability to “forge” the data going back to the keyboard to make new sounds.

The result is what you hear in the video linked after the break. Not exactly what [Nick] had in mind. After some snooping with the logic analyzer, he believes the issue is that the Arduino can’t respond as fast as the original NEC chip did. He’s now got an NVRAM chip on order to replace the original NEC chip; the idea is that he can still use the Arduino to reprogram the NVRAM chip when he wants to play around with the sound.

We’ve covered some pretty fancy circuit bent instruments here in the past, but if you’re looking for something a bit easier to get your feet wet we ran a start-to-finish guide back in the Ye Olden Days of 2011 which should be helpful.

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