synth

127 Articles

Teenage Engineering The Raspberry Pi

September 5, 2017 by 22 Comments

The Teenage Engineering OP-1 is a tiny, portable synthesizer loaded up with 4-track recording, a sampler, sequencers, and a quite good synthesis engine. It also fits in your pocket and looks like a calculator built in West Germany. As you would expect with a synth/sampler/sequencer, you can save sounds, tracks, and other creations to a computer. [Doug] thought if you can connect it to a laptop, you can also connect it to a Raspberry Pi. He created an all-in-one storage solution for the OP-1 using only a Pi and a small character LCD.

The process of connecting the Pi to the OP-1 is pretty simple. First, plug a USB cable into the OP-1 and the Pi. Then, place the OP-1 into Disk Mode, the synth’s method of transferring files between itself and a computer. The Pi then synchronizes, changes the color of its character display from red to green, and becomes a web server available over WiFi where all the files can be accessed.

This is the bare minimum tech required to get files into and off of the OP-1. All you need is a bit of power and a USB connection, and all the files on the OP-1 can be backed up, transferred, or replaced without any other futzing around. It’s perfect for the minimalist OP-1, and a great example of how handy a WiFi enabled Pi can be.

Thanks [Pator] for sending this one in.

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Hackaday Links: September 3, 2017

September 3, 2017 by 35 Comments

The TI-83, TI-84, and TI-86 have been the standard graphing calculators in classrooms for two decades. This is the subject of an xkcd. Now, hopefully, there’s a contender for the throne. Numworks is a graphing calculator that looks like it was designed in at least 2006 (so very modern), and apparently, there’s a huge community behind it.

Juicero is shutting down. No one could have seen this one coming. The Juicero was a $700 press that turned proprietary, DRM’ed juice packs into juice and garbage. It was exquisitely engineered, but it turns out very few people want to spend thousands of dollars per year on DRM’ed juice. Oh, since the Juicero phones home, those $700 presses probably won’t work in the future.

Are you in the Bay area? Do you need test equipment? There’s a gigantic auction happening somewhere around San Jose. [Dave] tipped everyone off to this one, and this auction is pretty freakin’ spectacular. Spectrum analyzers, signal gens, a ‘mega zoom’ oscilloscope, and 4-channel, 500 MHz scopes for $50. There are a thousand lots in this auction. It’s nuts.

Everybody loves PCB art, and [Uri] has a guide for designing custom, functional electronic circuit boards. The toolchain used in this guide is Inkscape and KiCad, with blinky hearts, blinky pandas, and other blinky PCBs.

This one is a little out there even for us. Here’s how you build your own AA batteries. It’s a dozen #10 copper washers, a dozen or so #10 zinc washers, some cardboard, vinegar, salt, and some heat shrink tubing. The assembly of this battery is exactly what you would expect, and yes, it does work. Here’s the thing, though: The very crude tests suggest these batteries have a capacity of about 800-1000 mAh, which is far more than we would expect. Who has a programmable load and wants to do a few experiments? Also, these batteries are ‘rechargeable’ by taking them apart, sanding the crud off each washer, and adding new electrolyte.

[Jan] has made a name for himself stuffing synthesizers into tiny little microcontrollers. The latest project is the Infinity37, a polyphonic synth with MIDI, envelopes, and a whole bunch of cool stuff. Check out the video.

[rctestflight] is building a solar powered aircraft. It’s has a beautiful wing studded with solar panels. The latest flight was four hours, long enough to make piloting a plane through some FatSharks extremely tedious. Future developments will probably include a MPPT charging solution, and probably an autopilot.

Making Synths Out Of Audio Cassettes

July 12, 2017 by 16 Comments

8bit Mixtapes are simple Arduino-based sound and beat generators based on ATtiny 84s and 85s and designed fit inside old audio cassettes, or at least be about that size. Founded by [Dusjagr], [Ucok] and [Lyok], and including participants from around the globe, 8bit Mixtapes are small synthesizers that play one-line algorithmic symphonies, simple sound generators that work off of a single line of code.

The project has been going on for a number of years, with several different iterations released over the years–the most recent is the Mixtape NEO, released about a month ago that features audio bootloading and a row of NeoPixel LEDs. It’s well documented and fully open source, with a code repository and wiki. The arty PCBs look great as well!

8bit Mixtapes are a natural project for electronics students to tackle. An ATtiny85 with two pots and two buttons? Pretty simple, and the musical payoff makes it a cinch for one-day workshops. The code simplicity makes it easy to modify the software as well.

Quirky synths are Hackaday’s bag, including one we published previously that controls a hexagonal matrix of LEDs.

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Dumping Synth ROMs And Avoiding Bitrot

June 21, 2017 by 24 Comments

Bitrot is setting in, and our digital legacy is slowly turning to dust. Efforts preserve our history are currently being undertaken numerous people around the Internet, and [Jason Scott] just got an automated CD ripper, so everything is kinda okay.

However, there is one medium that’s being overlooked. ROMs, and I don’t mean video game cartridges. In the 80s, mask ROMs were everywhere, found in everything from talking cars to synthesizers.

[Ali] bought a Korg i5m workstation from eBay a few years ago, but this unit had a problem. Luckily, he had a similar synth with the same samples stored on board. There was only one way to find out if bitrot was the cause: desoldering the chips and dumping all the information.

After fiddling around with his broken synth, [Ali] still had a problem with the sound output. Deciding the ROM chips had to be the issue, [Ali] desoldered the chips and ordered a breadboard SOP44 adapter after deciding soldering wires to each lead of the chip was a bad idea. This adapter was connected to an Arduino Mega — still the best tool for weird tasks like this — and the contents of the ROM were dumped to a PC with the help of a helpful Arduino sketch.

Dumping the ROMs took about 15 minutes, and that’s if he was able to maintain a good connection between the chip and Arduino for that long. [Ali] wrote an improved ROM reader after much trial and error, and was eventually able to get the same data out of the same chip eventually.

While the broken synth hasn’t been repaired yet, at least [Ali] has the important bits off of this antique instrument. That’s good enough for now, but [Ali] intends to take this project to completion and get those vintage samples playing out of this great old synth.

 

3D Printing A Synthesizer

May 12, 2017 by 13 Comments

Before there were samplers, romplers, Skrillex, FM synths, and all the other sounds that don’t fit into the trailer for the new Blade Runner movie, electronic music was simple. Voltage controlled oscillators, voltage controlled filters, and CV keyboards ruled the roost. We’ve gone over a lot of voltage controlled synths, but [Tommy] took it to the next level. He designed a small, minimum viable synth based around the VCO in an old 4046 PLL chip

For anyone who remembers [Elliot]’s Logic Noise series here on Hackaday, this type of circuit should be very familiar. The only thing in this synth is a few buttons, a variable resistor for each button, and the very popular VCO for an analog square wave synth.

The circuit for this synth is built in two halves. The biggest, and what probably took the most time designing, is the key bed. This is a one-octave keyboard that’s completely 3D printed. We’ve seen something like this before in one of the projects from the SupplyFrame Design Lab residents, though while that keyboard worked it was necessary for [Tim], the creator of that project, to find a company that could make custom key beds for him.

The rest of the circuit is just a piece of perf board and the 4046. This project is all wrapped up in a beautiful all-wood enclosure with 3D printed hinges, knobs, and a speaker grille. The sound is phenomenal, and exactly what you want from a tiny monophonic square wave synth. You can check out a video of that below.

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DIY Tiny Single-PCB Synthesizer

May 9, 2017 by 20 Comments

[Jan Ostman] has been pushing the limits of sound synthesis on the lowly AVR ATMega microcontrollers, and his latest two project is so cute that we just had to write it up. The miniTS shares the same basic sound-generation firmware with his previous TinyTS, which we’ve covered here before, but adds a lot more keys, an OLED, and MIDI, while taking away some of the knobs.

Both feature keyboards that are just copper pads placed over a ground plane, and the code does simple capacitive-sensing to figure out if they’re being touched or not. The point here is that you could pick up a PCB from [Jan] on the cheap, and experiment around with the code. Or you could just take the code and make a less refined version for yourself with a cheapo Arduino and some copper plates.

Either way, we like the combination of minimal materials and maximum tweakability, and think it’s cool that [Jan] shares the code, if not also the PCB designs. Anyone with PCB layout practice could get a clone worked up in an afternoon, although it’s going to be cheaper to get these made in bulk, and you’re probably better off just buying one from [Jan].

A Mess Of Wires Turned Into An Analog Synth

February 24, 2017 by 44 Comments

Over on YouTube, [GumpherDM3] built one of the greatest musical projects we’ve seen in a long time. It’s an analog synthesizer that is one of a kind. It’s going to stay one of a kind, too: no one would ever want to copy this mess of wires and perfboard that was successfully turned into a complete musical instrument.

The design of this synth is what you would expect from something that draws its inspiration from semimodular synths such as the Minimoog and Korg MS20. There are four VCOs on this synth, two audio and two used for the LFOs. A four-pole low pass filter, VCA, and two envelope generators round out the purely analog portion of the build. There’s an arpeggiator in there too, which makes for a really great demo video (below).

Inside, this is a true analog synth with the VCOs, filter, and VCA built around the LM13700 transconductance amplifier. The build log shows these chips spread out around half a dozen breadboards before being plugged into sockets soldered to handwired perf board. This synth is a one of a kind instrument – no one would want to build this thing twice.

Additional features include an Arduino with a MIDI in port sending out CV signals to the analog part of the synth. This thing has everything you would expect from a modern take on an analog synthesizer, and it sounds good, too.

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