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.
Continue reading “Pedal-Pi, Simple Programmable Guitar Pedal” →
OpenStomp’s Coyote-1 is now available for $349. The guitar effects pedal lets users design and upload their own effects to the device. It has two stomp switches with LEDs, an LCD display, and four user assignable knobs. The back has 1/4″ in/out and one selectable 1/4″. It also features NTSC composite out, a headphone jack, mini-USB for uploading, and an RJ11 I2C bus for expansion. The processor is a Parallax Propeller Chip. While the OS on the pedal is open source, the hardware design and effect design software are not. You can check out the source and product manual on their forum. If you’re more interested in breadboarding hardware, you might like the Beavis Board we covered earlier.
[via Create Digital Music]
[jonboytang] documented his construction of a clone of the famous Tube Screamer overdrive pedal from a set of plans found at tonepad. The tonepad site says you can use the plans to build either a TS-9 or a TS-808, both of which have been classic staples in every guitar player’s setup since the 70s. Although the old parts are no longer available, these new variants still have a really nice sound.
This project is really just a look into [jonboytang]’s etching and enclosure building process, but it may be useful for someone. The build and the circuit look really simple so this would be a great project for guitar players looking to learn how to etch their own PCBs. If you need more information on etching, we would suggest starting out by reading our How-To on etching single sided PCBs. If you are lazy and would rather spend a little money, check out tonepad’s online store. They have a board for this project and many others.
Beavis Audio has recently released the Beavis Board, a kit to help fledgling guitar pedal builders. The kit addresses four typical problems in this endeavor: learning to solder, dealing with breadboards, sourcing parts, and making sense of schematics. By including a breadboard/psu/switch combo and tons of other parts as well as informative and easy to read schematics, all of these problems are alleviated, allowing eager builders to get to work right out of the box.
The kit costs $249 and we’re guessing it’s a little too “entry level” for most of you. It has a highly informative manual in PDF format. You could use that to get ideas and then source your own parts. Have any of you built a guitar pedal specifically for prototyping?
[via Music Thing]