Saving Old Voices By Dumping ROMs

January 20, 2016 by Elliot Williams 41 Comments

Some people collect stamps. Others collect porcelain miniatures. [David Viens] collects voice synthesizers and their ROMs. In this video, he just got his hands on the ultra-rare Electronic Voice Alert (EVA) from early 1980s Chrysler automobiles (video embedded below the break).

Back in the 1980s, speech synthesis was in its golden years following the development of TI’s linear-predictive coding speech chips. These are the bits of silicon that gave voice to the Speak and Spell, numerous video game machines, and the TI 99/4A computer’s speech module. And, apparently, some models of Chrysler cars.

We tracked [David]’s website down. He posted a brief entry describing his emulation and ROM-dumping setup. He says he used it for testing out his (software) TMS5200 speech-synthesizer emulation.

The board appears to have a socket for a TMS-series voice synthesizer chip and another slot for the ROM. It looks like an FTDI 2232 USB-serial converter is being used in bit-bang mode with some custom code driving everything, and presumably sniffing data in the middle. We’d love to see a bunch more detail.

The best part of the video, aside from the ROM-dumping goodness, comes at the end when [David] tosses the ROM’s contents into his own chipspeech emulator and starts playing “your engine oil pressure is critical” up and down the keyboard. Fantastic.

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Retrotechtacular: The Theremin Terpsitone

January 14, 2016 by Kristina Panos 11 Comments

Léon Theremin built his eponymous instrument in 1920 under Soviet sponsorship to study proximity sensors. He later applied the idea of generating sounds using the human body’s capacitance to other physical forms like the theremin cello and the theremin keyboard. One of these was the terpsitone, which is kind of like a full-body theremin. It was built about twelve years after the theremin and named after Terpsichore, one of the nine muses of dance and chorus from Greek mythology.

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Oh Baby, Baby10 – Build A Classic Analog Music Sequencer

January 14, 2016 by Nava Whiteford 20 Comments

Recently I’ve been learning more about classic analog music synthesizers and sequencers. This has led me to the Baby10, a classic and simple analog sequencer design. In this article I’ll introduce its basic operation, and the builds of some awesome hackers based on this design.

Sequencers produce, a sequence of varying voltages. These control voltages (CV) can then be use to control other components. Often this is a simple tone generator. While the concept is simple, it can produce awesome results:

A basic sequencer is a great beginners project. It’s easy to understand the basic operation of the circuit and produces a satisfyingly entertaining result. The Baby 10 was originally published in a column called “Captain’s Analog”, but has now been widely shared online.

The circuit uses the 4017, a simple CMOS decade counter. The 4017 takes an input clock signal then sequentially outputs a high pulse on each of 10 output pins. As such, the 4017 does almost everything we need from a sequencer in a single IC! However, we want our sequencer to output a varying voltage which we can then use to generate differing tones.

To accomplish this variable resistors are connected to each of the output pins. A diode in series with the variable resistor stops the outputs fighting against each other (in layman’s terms).

To make the sequencer more visually attractive (and give some feedback) LEDs are often also added to the output of the 4017. A complete Baby 10 sequencer is shown in the schematic below. The original circuit used 1N917s, these are no longer available but the part has been replaced by the 1N4148.

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Second Skin Synth Fits Like A Glove

January 12, 2016 by Kristina Panos 5 Comments

California textiles artist and musician [push_reset] challenged herself to make a wearable, gesture-based synth without using flex-sensing resistors. In the end, she designed almost every bit of it from the ground up using conductive fabric, resistive paint, and 3-D printed parts.

A couple of fingers do double duty in this glove. Each of the four fingertips have a sensor made from polyurethane, conductive paint, and conductive fabric that is connected to wires using small rivets. These sensors trigger different samples on an Edison that are generated with Timbre.js. The index and middle fingers also have knuckle actuators made from 3-D printed pin-and-slot mechanisms that turn trimmer pots. Bending one knuckle changes the delay timing while the other manipulates a triangle wave.

On the back of the glove are two sensors made from conductive fabric. Touching one up and down the length will alter the reverb. Sliding up and down the other alters the frequency of a sine wave. [push_reset] has kindly provided everything necessary to re-create this build from the glove pattern to the STL files for the knuckle actuators. Check out a short demonstration of the glove after the break. If you love a parade, here’s a wearable synth that emulates a marching band.

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The Smallest MIDI Synthesizer?

January 8, 2016 by Richard Baguley 32 Comments

Dang. [Mixtela] has just managed a seriously cool hack: running an entire MIDI synthesizer on an ATTiny85 to create what he claims is the worlds smallest MIDI synthesizer. That’s it on the left, next to a standard MIDI cable plug. The whole thing is so small it fits inside a MIDI plug and can run off the power supplied by the MIDI output, driving a small pizeo buzzer. Considering that the ATTiny85 has just 8Kb of memory and 512 bytes of RAM, this is no small feat (get it?). To create the sound, [Mixtela] simply drives the buzzer with PWMed square waves, creating the glorious early chiptunes sound that every retro gamer will recognize.

He even decided to implement some MIDI commands beyond just playing notes, including pitch bending, and is considering ways to add polyphony to his small miracle. Sure, it isn’t going to win any awards for sound quality, and without optoisolators it doesn’t really fit the MIDI spec. But it works, and remember that MIDI synthesizers used to be big, expensive devices that required a degree in sound engineering to program. Now, thanks to hackers like [Mixtela], you can build your own from parts that cost only a couple of dollars.

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32C3: 20 Oscillators In 20 Minutes

January 3, 2016 by Elliot Williams 25 Comments

In terms of implausible stand-up comedy, [Darsha]’s “20 Oscillators in 20 Minutes” is pretty far out there. First of all, she’s sitting down, with googly eyes on her multimeter, and five breadboards and a mess of 9V batteries laid out in front of her. “Has anybody built electronics before? Has anybody built electronics in front of this many people before? Yeah, so you’d better f**king be nice.” And she’s off!

“Square waves are really good for your speakers.” And a few seconds later, a lub-dub beat-frequency oscillator filled the hall. And then there’s the stand-up clichés: “Anyone in the audience from Norway?!” And “Anyone know what chip I’m using here?” (The 555.) A heckler, or participant, shouts up “What are you doing?” She responds “Building this!” and shows a sketch of the basic layout.

She baits the audience — “Do you want to ask me about duty cycles?” — and tells stories: “And then one time the solder fell in my lap and burned through my crappy jeggings. Who knows what jeggings are? Whooo!!” All the while the clicking gets louder and more complicated.

Then there’s the suspense. “11 minutes left? Shit, I dunno if I’m going to make it this time!” She’s visibly panicked. A question: “How do you protect the outputs from overvoltage?” “I don’t. (pause, laughter) I use some filter caps and just, well, hope that you guys have good insurance.”

Nearing the home stretch, there’s this quasi-rhythmic ticking and pulsing slowly building up in the background. She plugs in another capacitor, and the crowd spontaneously applauds. A little bit later, she shouts “Is it loud enough?” over the din and turns it down. At the end, the timing’s getting really tight, and she calls up someone to help from the audience.

We won’t spoil it, naturally. You’ll just have to watch it run to the end. We laughed, we cried. It was better than Schroedinger’s cats.

(We’d use hex inverters.)

The Hovalin: Open Source 3D Printed Violin Sounds Great

January 2, 2016 by Adam Fabio 26 Comments

[Matt and Kaitlin Hova] have created The Hovalin, an open source 3D-printed violin. Yes, there have been 3D-printed instruments before, but [The Hovas] have created something revolutionary – a 3D printed acoustic instrument that sounds surprisingly good. The Hovalin is a full size violin created to be printed on a desktop-sized 3D printer. The Hovas mention the Ultimaker 2, Makerbot Replicator 2 (or one of the many clones) as examples. The neck is one piece, while the body is printed in 3 sections. The Hovalin is also open source, released under the Creative Commons Attribution Non-Commercial Share Alike license.

A pure PLA neck would not be stiff enough counter the tension in the strings, so [The Hovas] added two carbon fiber truss rods. A handful of other components such as tuners, and of course strings, also need to be purchased. The total price is slightly higher than a $60 USD starter violin from Amazon, but we’re betting the Hovalin is a better quality instrument than anything that cheap.

The Hovalin was released back in October. There are already some build logs in the wild, such as this one from [Emulsifide]. Like any good engineering project, the Hovalin is a work in progress. [Matt and Kaitlin] have already released version 1.0.1, and version 2.0 is on the horizon. Hearing is believing though, so click past the break to hear [Kaitlin] play her instrument.

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