Designing The Atom Smasher Guitar Pedal

July 24, 2017 by 14 Comments

[Alex Lynham] has been creating digital guitar pedals for a while and after releasing the Atom Smasher, a glitchy lo-fi digital delay pedal, he had people start asking him how he designed digital effects pedals rather than analog effects. In fact, he had enough interest, that he wrote an article on it.

The article starts with some background on [Alex], the pedals he’s built and why he chose not to work on pedals full-time. Eventually, the article gets to the how [Alex] designed the Atom Smasher. He starts by describing the chip he used, the same one that many hobbyists, as well as commercial builders, use for delay based effects – the SpinSemi FV-1.

The FV-1 is a SMD chip used for digital delays and other effects that require a delay line – reverbs, choruses, flangers, etc. It’s programmed with an assembly-style language called SpinASM. [Alex] goes over some of the tools and references he used when designing for the pedal. He also has a list of tips for would-be effect pedal designers which work whether you’re designing digital or analogue effects.

[Alex] ends his article saying that, in the future, he might make the schematic and code available, but for the moment he’s not. The FV-1 is an interesting chip, and [Alex]’s article gives a nice high-level look at its features and how to develop for it. For some interesting guitar pedal related articles, check out this one using effects pedals to get better audio in your car, and here’s one about playing with DSP and designing a pedal with it.

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MIDI Guitar Pedals

November 20, 2016 by 8 Comments

Ever since Jimi Hendrix brought guitar distortion to the forefront of rock and roll, pedals to control the distortion have been a standard piece of equipment for almost every guitarist. Now, there are individual analog pedals for each effect or even digital pedals that have banks of effects programmed in. Distortion is just one of many effects, and if you’ve built your own set of pedals for each of these, you might end up with something like [Brian]: a modular guitar pedal rack.

ae0fmjxTaking inspiration from modular synthesizers, [Brian] built a rack out of wood to house the pedal modules. The rack uses 16U rack rails as a standard, with 3U Eurorack brackets. It looks like there’s space for 16 custom-built effects pedals to fit into the rack, and [Brian] can switch them out at will with a foot switch. Everything is tied together with MIDI and is programmed in Helix. The end result looks very polished, and helped [Brian] eliminate his rat’s nest of cables that was lying around before he built his effects rack.

MIDI is an extremely useful protocol for musicians and, despite being around since the ’80s, doesn’t show any signs of slowing down. If you want to get into it yourself, there are all kinds of ways that you can explore the studio space, even if you play an instrument that doesn’t typically use MIDI.

IPad Control For Guitar Pedals

May 28, 2016 by 4 Comments

[gutbag] is a guitarist. And guitarists are notorious knob-twiddlers: they love their effects pedals. But when your music involves changing settings more than a few times in the middle of a song, it can get distracting. If only there were little robot hands that could turn the knobs (metaphorically, sorry) during the performance…

Tearing into his EHX Pitch Fork pedal, [gutbag] discovered that all of the external knob controls were being read by ADCs on the chip that did all of the processing. He replaced all of the controls with a DAC and some analog switches, coded up some MIDI logic in an ATmega328, and built himself a custom MIDI-controlled guitar pedal. Pretty slick, and he can now control it live with his iPad, or sequence the knobs with the rest of their MIDI system.

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This wasn’t [gutbag]’s first foray into pedal automation, however. He’d previously automated a slew of his pedals that were already built to take control-voltage signals. What we like about this hack is the direct substitution of DAC for potentiometers. It’s just hackier. (Oh, and we’re envious of [gutbag]’s lab setup.)

This isn’t the first time we’ve covered [gutbag]’s band, Zaardvark, either. Way back in 2013, we featured an organ-pedal-to-MIDI hack of theirs. Keep on rockin’.

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modded guitar pedal

Guitar Pedal Hack Via Manufacturer’s Shortcut

October 17, 2014 by 11 Comments

There seems to be no shortage of manufacturers that cut costs by using similar components across a wide range of products. This isn’t necessarily a bad thing though, since it makes it easier for someone with some know-how to quickly open up the product and figure out how to get more use out of it. [Lewin] noticed some peculiarities on the PCB of his EHX Screaming Bird guitar pedal, and used a manufacturer’s shortcut to turn this treble-boosting pedal into a flat booster.

Once [Lewin] removed the case, he noticed that there were some unpopulated pads on the PCB. Additionally, the potentiometer was labelled as 10k, but a 100k was actually installed. These were indications that something was awry, so after poking around on the internet, [Lewin] now believes that the same PCB was used to make at least three different effects pedals with similar internal structures.

The Screaming Bird pedal was a little harsh for [Lewin]’s taste, so he changed out some capacitors on the board to get it closer to the flat booster. There are some other things that could be changed, but now he has a pedal that suits his needs much more appropriately, thanks to the manufacturer making only minor changes across a range of similar products. Historically, guitar pedals are pretty easy to modify, but it’s nice that the manufacturer of these has made it so much simpler!

An Opensource Arduino Guitar Pedal

December 21, 2013 by 25 Comments

If you’re a guitarist, or know a guitarist, you probably know just how many guitar effects there are out there — but what if you could design your own effects?

[J Rodriguez] has just released his opensource Arduino guitar pedal shield, dubbed the pedalSHIELD. He designed it as a platform to learn about digital signal processing, effects, and synthesizers — without needing an in-depth knowledge of electronics or programming. It allows you to design your own effects in C/C++, or download from his own library online. Some of the downloadable presets include an octave pedal, reverb pedals, delay pedals, and even distortion pedals!

The pedal features three programmable potentiometers, two main switches, and the foot pedal switch. The shield plugs directly into an Arduino Due, and you can find all the schematics here and the parts list here. It was completely designed in KiCad which is an open source electronics CAD design suite.

Take a listen after the break to hear the pedal in action!

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Improving A Cheap Guitar Pedal

November 29, 2013 by 12 Comments

pedul

If something doesn’t suit your needs, just change it. That’s a motto we live by, and it looks like [Doug] took up the same creed when he modified a cheap effects pedal.

The victim of [Doug]’s soldering iron is a Danelectro BLT Slap Echo – a tiny, cheap pedal in Danelectro’s mini ‘food named’ pedal series. Stock, this pedal’s slap back echo is set to a fixed amount of time. [Doug]’s mod changes that.

The mod consists of desoldering a single SMD resistor and replacing that with a 50k pot [Doug] had lying around. After mounting the pot between the two stock knobs, the new and improved pedal had a variable length echo. There are a few more mods possible with this pedal – changing some of the resistors on the filter for a better sound, or even connecting the rate pot to a wah-style rocker pedal for some wobbly Echoplex or Space Echo action.

You can check out [Doug]’s gallery of pics here.

Putting Guitar Pedals In A Web Page

October 10, 2012 by 13 Comments

Only half of playing guitar – according to a few musician friends of mine – is moving your fingers up and down a fretboard and banging out some chords. The other half is the artistry of mastering your tone, usually through amp settings and stomp boxes.

Effects pedals – little boxes of electronics that go between the guitar and amp – are able to amplify and distort a guitar’s output, add reverb and delay, and even filter the tone via a wha or envelope pedal. These pedals can be simulated in software, but we can’t believe that they can now be emulated completely in JavaScript.

Pedalboard.js is a project put together by [dashersw], and aims to put a slew of pedals ‘in the cloud’ and turn editing and effects board as easy as building a web page.

The project is built around Webkit’s W3C audio API, allowing this virtual pedal board to work in Chrome, Safari, and other Webkit-enabled browsers. Pedals are programmed as nodes, each configurable to have and input, output, or analyzer that is able to modify the gain, wave shape, or filter of anything received by the line in on your computer.

Thee is a small demo of Pedalboard.js available here with a pre-recorded guitar track feeding into a few stomp boxes. It’s a pretty cool idea if you’d like to play around with a few guitar effect, but we can’t wait to see this bit of JavaScript implemented by effects pedal manufacturers allowing us to try before we buy.