Pedal-Pi, simple programmable guitar pedal

For several years, [Ray] and [Anna], the team behind ElectroSmash, have been smashing audio electronics and churning out some sweet DIY audio gear. This time around, they’ve built Pedal-Pi — a simple programmable guitar pedal based around the Raspberry-Pi Zero. It is aimed at hackers, programmers and musicians who want to experiment with sounds and learn about digital audio. A lot of effort has gone in to documenting the whole project. Circuit analysis, a detailed BoM, programming, assembly and background information on related topics are all covered on their Forum.

The hardware is split in to three parts. On the input, a MCP6002 rail-to-rail op-amp amplifies and filters the analog waveform and then a MCP3202 ADC digitizes it to a 12-bit signal. The Pi-Zero then does all of the DSP, creating effects such as distortion, fuzz, delay, echo and tremolo among others. The Pi-Zero generates a dual PWM signal, which is combined and filtered before being presented at the output. The design is all through hole and the handy assembly guide can be useful for novices during assembly.  The code examples include a large number of pedal effects, and if you are familiar with C, then there’s enough information available to help you write your own effects.

Even if you don’t plan on building one, technical background such as the Basics of Audio DSP in C for Raspberry Pi Zero, Using MCP3202 ADC with Raspberry Pi Zero and PWM Audio on Raspberry Pi Zero ought to make for interesting reading. Check out the video after the break detailing the build.

If you’d like to check out some of their earlier work, check out 1WAMP, an Open Hardware Guitar Amplifier and pedalSHIELD, an opensource Arduino Guitar Pedal.

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Designing the Atom Smasher Guitar Pedal

[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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Hackaday Links: February 5, 2017

A lot of people around here got their start in electronics with guitar pedals. This means soldering crappy old transistors to crappy old diodes and fawning over your tonez, d00d.  Prototyping guitar pedals isn’t easy, though, and now there’s a CrowdSupply project to make it easier The FX Development Board is just that — a few 1/4″ jacks, knobs, pots, power supply, and a gigantic footswitch to make prototyping guitar pedals and other musical paraphernalia easy. Think of it as a much more feature-packed Beavis Board that’s still significantly cheaper.

How do Communicators in Star Trek work? Nobody knows. Why don’t the crew always have to tap their badge before using it? Nobody knows. How can the com badge hear, ‘Geordi to Worf’, and have Worf instantly respond? Oh, we’ve argued about this on IRC for years now. Over on Hackaday.io, [Joe] is building a Star Trek com badge. The electronics are certainly possible with modern microcontrollers, but for the enclosure, we’ll have to review a few scenes from Time’s Arrow and The Enemy.

[Alois] was working with an Intel Edison on a breadboard. He was generating a signal, and sending it through a little tiny breadboard wire to an oscilloscope. The expected waveform should have been a nice square wave at 440MHz. What he got out of this wire was a mess. You shouldn’t use long wires when probing circuits. That little breadboard wire was a perfect radiator for 440MHz, and the entire setup turned into an antenna.

[Douglas] is running a Kenwood TM-D710A as his amateur radio rig. This radio does APRS stuff, but it requires an external GPS and power source to do it right. GPS receivers are now very small and very cheap, so [Douglas] just stuffed a GPS module inside his radio. The module itself is a GP-20U7, a tiny GPS module the size of a postage stamp, and wired it up to a few pads on the radio PCB.

Here’s an upcoming Kickstarter that’s going straight to the front page of Boing Boing. It’s Pong, in coffee table format which we first saw last Spring. Instead of racing the beam, this version of Pong is mechanical. The ball is a cube, the paddles are slightly longer cubes, and the entire game is a highly refined CNC machine. Here’s something from seven years ago that’s also Pong in coffee table format. Pongmechanik is electromechanical Pong, built entirely out of switches, relays, and a few motors.

Two Guitars, Two Amps, And Three Pole Dual Throw

[Alexbergsland] plays electric guitar. More accurately, he plays two electric guitars, through two amps. Not wanting to plug and unplug guitars from amps and amps from guitars, he designed an AB/XY pedal to select between two different guitars or two different amps with the press of a button.

The usual way of sending a guitar signal to one amp or another is with an A/B pedal that takes one input and switches the output to one jack or another. Similarly, to switch between two inputs, a guitarist would use an A/B pedal. For [Alex]’ application, that’s two pedals that usually sell for $50, and would consequently take up far too much room on a pedalboard. This problem can be solved with a pair of 3PDT footswitches that sell for about $4 each. Add in a few jacks, LEDs, and a nice aluminum enclosure, and [Alex] has something very cool on his hands.

The circuit for this switcher is fairly simple, so long as you can wrap your head around how these footswitches are wired internally. The only other special addition to this build are a trio of LEDs to indicate which output is selected and if both inputs are on. These LEDs are powered by a 9V adapter embedded in the pedalboard, but they’re not really necessary for complete operation of this input and output switcher. The LEDs in this project can be omitted, making this a completely passive pedal to direct signals around guitars and amps.

Hackaday Links: September 4, 2016

Nozzle socks! Just keep saying, ‘nozzle socks’ until the semantic satiation undoes any semblance of sanity. E3D, makers of the world’s finest 3D printer hotends have released silicone nozzle covers that prevent caramelized plastic gunking up your hot end. Nozzle socks.

Let’s talk guitar pedals. If you’ve ever built your own guitar pedal, you probably stuffed it inside a Hammond enclosure. There’s more to guitar pedal enclosures than custom-painted electronic boxes, and arguably the best enclosures are the ‘Boss’ style – a metal cover over the switch that can be removed to access the battery independently of the circuit. Now you can buy this type of enclosure. [Rixen] is producing blank die-cast aluminum pedals that look so much better than the standard Hammond enclosure.

The Antonov AN-225 is the largest and heaviest airplane in the world. Only one was built. For the last thirty years, a second airframe, about 70% complete, has sat in a field or hangar in the Ukraine, waiting for someone to put it into service. After numerous false starts over the past decade or so, the second AN-225 is finally being built.

The Hackaday Retro edition is our version of Hackaday optimized for embedded devices. When someone gets some old hardware on that vast World Wide Web and manages to pull up the retro edition, we like to celebrate. [Michael] recently got his old Amiga 1200 online and managed to find the software and hardware to get this machine on the net. Inside the A1200 is a 4GB CompactFlash, an ACA 1232 accelerator card with 128MB of RAM and a 33MHz 030. The network is handled by a Linksys EC2T card, and the software is KS3.0, WB3.1, MiamiDX IP stack IBrowse 2.4, and a bunch of 3rd party libs he can’t remember. Here’s a pic.

On a related note, I haven’t touched the Hackaday Retro Edition in years. Right now, it’s just a script running every five minutes that assembles five random posts from the first 15,000 Hackaday posts since the beginning of time. The retro edition does what I want it to do, but I’m wondering if it can be better. If you have an idea of how to improve the Retro Edition, leave a note in the comments.

Hackaday Links: January 17, 2016

The BBC has commissioned a new series of Robot Wars. This is not Battlebots; that show was revived last year, and a second season will air again this summer. Robot Wars is the one with the ‘house’ robots. We would like to take this opportunity to remind the BBC that Robot Wars is neither Scrapheap Challenge nor Junkyard Wars, and by virtue of that fact alone is an inferior show.

[Fran] is a favorite around these parts. She’s taken apart a Saturn V Launch Vehicle Digital Computer, visited the Smithsonian Air and Space Museum warehouse, and is the occasional host of the Dinosaur Den with [Bil Herd]. Now, she’s relaunching her line of guitar pedals. ‘Boutique’ pedals are a weird market, but with the help of a few manufacturers, [Fran] is bringing her Peachfuzz pedal back to life through Kickstarter.

Want to be an astronaut? Here’s the application.

Here’s your monthly, ‘WTF is this thing on eBay’ link. It’s a clamshell/toilet seat iBook (c.2000), loaded up with an Intel i5 Broadwell CPU, 128 GB of Flash storage, 4 GB of RAM, a 12″ 1024×768 LCD, Gigabit Ethernet, WiFi, Bluetooth, and runs OS X El Capitan. I might be mistaken, but it looks like someone took the motherboard out of a 2015 MacBook Air, crammed it into a sixteen year old computer, and put it up on eBay. I’m not saying that’s what it is; this is from China, and there are people over there making new improved motherboards for a Thinkpad x61. Weirder stuff has already happened.

In the last installment of the Travelling Hacker Box, I asked if anyone can receive mail in Antarctica. A person with friends in the British survey team emailed me, but nothing came of that. It’s summer, so if Antarctica is going to happen, it needs to happen soon.

Hackaday Links: August 23, 2015

Dutch security conference! It’s called hardwear.io, it’ll be in The Hague during the last week of September, and they have the CTO of Silent Circle/Blackphone giving the keynote.

Baltimore’s awesome despite what the majority of the population says, and they have a few hackerspaces. One of them has an Indiegogo going right now to save the space. Want a tour of the space? Here you go.

[Fran Blanche] made it on to the Amp Hour. Included in this episode are discussions about the boutique guitar pedal market and the realities of discarded technology that took us to the moon.

Speaking of electronics podcasts, SolderSmoke is 10 years old now.

TARDIS-shaped guitars are nothing new, but [Gary] from the LVL1 hackerspace in Louisville, KY is making an acoustic one. The neck is, of course, taken from another guitar but the entire TARDIS-shaped body is custom-made. Now do resonance calculations on something that’s bigger on the inside.

Think German-made means German quality? [AvE], [Chris], or whatever we call him did a teardown of a Festool Track Saw. It’s a thousand dollar tool that will start to stink in a few years and has bearings that don’t make any sense.

Love 8-bit? There’s a Kickstarter from 8-bit generation for a documentary about the love, loss, resurrection and continuation of old computers. Dozens of very interesting interviews including one from our own [Bil Herd]