music hacks | Raspberry Pi

Music hacks: guitar effects, and an electronic tuner

Regular readers will know that I’m a particular sucker for musical hackery involving a Raspberry Pi. I’ve got two really terrific examples to share today.

First up, here’s a guitar effects box from Pierre Massat. He emails to say:

I write a blog about how to make guitar effects with computers running Pure Data in real-time. When I first heard about the Raspberry Pi I thought it would be great if I could use it for the same purpose. It would only be much cheaper, and much smaller than my current laptop, and could fit in my hand-made stompbox.

Recent improvements in Raspbian have finally made this possible, and this makes me very happy! The Raspberry Pi is now actually capable of running rather demanding Pure Data patches in (quasi-) real-time (at least with a latency that’s low enough to play live with it).

I quickly assembled a small patch to test it and make a video to demonstrate that it actually works very well.

It is obviously not the use the RPi was originally intended for, but to me (and I’m sure to other musicians as well), this sounds like a revolution.

There’s no trick, the Pi really IS doing all the DSP work. A reader posted a comment to ask where the computer was

Pierre has blogged about the hardware setup, and has made some video of the box in action. The really sucky thing about my job is that I get to see all of this incredibly cool stuff, and don’t have any free time to emulate it myself. This is a project I have earmarked for trying out when I retire.

Great socks, by the way, Pierre.

Meanwhile, Blacktonedev on YouTube has been using his Raspberry Pi, a 7-segment display, a handful of resistors and a collection of leds to make an electronic tuner. The only documentation available is what he’s left on YouTube, but it’s pretty exhaustive, and I’ve copied and pasted it here for you under the video, We were really impressed by this project; if you’re reading this, Blacktonedev, please get in touch so I can credit you properly!

Hardware & equipment
Tuner is using 15 LEDs (7 red (lower half) + 7 red (upper half) + 1 green (center)) for displaying frequency and 7-segment display for displaying the matched note (dot in the bottom-right corner signifies a sharp note e.g. A#, G#, D# etc.). MCP23017 16-bit I2C IO Expander is used for controlling frequency LEDs, 7-segment display is controlled via GPIO pins on Raspberry Pi. Everything connected with resistors, jumper-wires and 840-contact BreadBoard (using Starter Kit-B for Raspberry Pi from skpang.co.uk). A web-cam (Microsoft LifeCam) connected to Raspberry Pi is used for recording & analyzing audio.

Software & theory
Java is used for controlling everything. Pitch detection is done by Autocorrelation method inspired by John Montgomery’s great 5K tuner.

Photo of the tuner
https://www.dropbox.com/s/h03jlktlyf0…

Dedicated to the whole Raspberry Pi community.

Links
Raspberry Pi: http://www.raspberrypi.org
Theory (pitch detection + autocolleration):http://en.wikipedia.org/wiki/Pitch_de… +http://en.wikipedia.org/wiki/Autocorr…
5K tuner by John Montgomery:http://www.psychicorigami.com/2009/01…
GPIO equipment (skpang):http://www.skpang.co.uk/catalog/raspb…

BeetBox – music employing capacitive touch, root veg and a Pi

This has to win Liz’s Project of the Year Award (there is no prize).

Regular readers will know that I go all wibbly over music projects that use the Raspberry Pi. And that I’m a very keen cook. What festive joy, then, to find a link to BeetBox in my Twitter stream. This project, from Scott Garner, wires up some root vegetables to a Pi (hidden, alongside an amp and speakers, in what I am going to call the beetroot mount – a lovely thing handmade from poplar wood) and seduces you into…touching them, to make sweet, sweet music.

BeetBox Demo from Scott Garner on Vimeo.

Seriously – is this not the best thing ever? You can read more about it on Scott’s website, where there’s more video; and you can find code to bring joy into the contents of your own fridge’s crisper drawer at Github.

Come on, folks. Next, we want to see a carrot piano.

Music hacks, Raspberry Pi synthesiser

We’ve spent the last few days at the Turing Festival in Edinburgh. And the best thing we did (that party with the free whisky and the accelerometer-jousting aside) was visiting Music Hack Scotland, where we saw some pretty amazing hacks being produced at the closing show-and-tell. Favourites? Electronics newbie Annie’s hand-soldered metronome (a kick-ass demonstration that soldering is easy); the Raspberry Pi-driven soft toy/guitar hybrid (The Ducktar – I’m hoping for some video from the makers if they find some time); and an ambient music-generating unicycle.

There’s another music hack in Iceland in a couple of months. Eben and I are currently juggling our schedules to try to make it out there for the event; the hacker community in Reykjavik are some of the nicest folks we’ve met since we’ve been doing this, and the music hack promises to be another brilliant weekend.

Meanwhile, back in England…

Piana graphical user interface

When we got home, head full of ideas about encouraging people to port Max to the Raspberry Pi, we found a mail waiting for us from Omenie, one of our forum members. I really wish we’d known about this before Music Hack Scotland. He’s building a virtual analogue synthesiser called Piana (geddit?) with the Raspberry Pi, and it is absolutely one of the most exciting bits of work-in-progress I’ve seen being done with the Pi so far. (Full disclosure: a Raspberry Pi being used as a synthesiser is perfectly calculated to press all my buttons. I love it.)

Omenie says:

Later than anticipated, please check out a Raspberry Pi being – and I do not exaggerate – the best-sounding synth I’ve ever played with for under £500, never mind under £50. It was a hideous effort to get even 4 note polyphony out of it, am hoping to still get 8 by more aggressive tuning although guts have already been bust.

He’s blogging about Piana’s progress, and things are moving fast, so if you’re interested, it’s well worth checking in regularly. I hope we’ll be featuring Piana more here too as she becomes more mature. Thanks Omenie; we look forward to seeing and hearing more from you!