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The Digi-Gurdy

MIDI based electronic portable practice hurdy-gurdy.

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The hurdy-gurdy is an ancient musical instrument (10th century) with drones and melody strings bowed by a rotating wheel, played by pressing keys which contact them at different points. It has in more recent times featured in the TV series “Black Sails”, “Walking Dead” and also in the “God of War” games.
The major barrier for beginners is that they are very expensive and built to order with lead times of several months to a year. Rather like bagpipes, they are noisy when practicing. For pipers, practice chanters and e-chanters are available to solve this problem while nothing similar is available for the hurdy-gurdy.
The Digi-Gurdy therefore is an electronic hurdy-gurdy keybox, with correctly placed keys, that outputs MIDI via a USB cable to an attached laptop or phone running suitable MIDI player software, for practice anywhere using headphones.

What is it?

In addition to the above, a hurdy-gurdy also has drone strings and a buzzing rhythm section operated by varying the rotation speed of the crank handle. It has been described as the stringed equivalent of the bagpipes and, as with bagpipes, there are design variations in the folk traditions of different countries. Links to videos of real hurdy gurdy players are provided lower down this page.

The Digi-Gurdy is an electronic hurdy-gurdy keybox, with correctly placed keys, that outputs MIDI (an industry standard digital communication system for electronic musical instruments) via a USB cable to an attached laptop or phone running suitable MIDI player software. When used with headphones this would give you a low cost, portable, compact and silent means of playing the equivalent of the melody strings, i.e. something to learn to play on wherever you may be. It would not even require a battery as it would be powered via the USB cable.

Why?

1) Major barriers to entry for beginners are that while a playable electric guitar for example can be bought for around $200, a hurdy-gurdy is made to order by one of a few specialists and costs around $1500 even for a basic instrument with a waiting time of several months to a year.

2) In addition, it is noisy, making a good place to practice without upsetting your companions hard to find! This problem has been solved for bagpipe players with the availability of both practice chanters resembling a simple flute and electronic e-chanters allowing practice while wearing headphones.

3) Even if you do order one, you need something to learn to play in the meantime, while you are waiting for it to be built.

How it works:

The entire structure of my first attempt is 3D printed in ABS plastic. The keys press on micro-switches and the brain of the device is an Arduino Teensy 3.6 microcontroller. An OLED display shows you which note you are playing at any time.

I also envisage a Demonstration Mode which would play a selection of songs at the speed of your choosing while displaying the notes on the OLED screen as it goes.

At present it has a fold up handle held in the right hand which helps stabilize it while the melody is being played with the left hand. In the real instrument the right hand would turn a crank handle, which is a separate skill to be learned in its own right and I am investigating ways to simulate this action that remain compatible with the overall concept of a compact portable instrument.

Primary objective:

The ultimate aim of this is to produce a version 2 of the Digi-Gurdy either fully built or as a kit which could be assembled by someone around 14 years or older with basic soldering skills and the ability to complete a plastic model kit.

Version 1 is entirely 3D printed in bright red ABS blocks which are glued together, with a flip up OLED screen and a folding handle for the right hand which originally was an accessory for stabilizing an SLR camera. The files are attached below along with an assembly and use manual.

The next version needs to

i) Have a reduced number of printed parts and be easier to assemble.

ii) Be more robust.

iii) Have the option at least of adding in a simulated crank handle module.

Video examples of various styles of hurdy-gurdy players, in no particular order:

Nigel Eaton

Nigel Eaton with Led Zeppelin

Gregory Jolivet

Harry Wass

Efren Lopez

Tobie Miller

Andrey Vinogradov

Mr Wehle, Prague street performer

Example of a younger player, Patty Gurdy.

Video about the Black Sails TV series soundtrack

BuildManual V1.5.pdf

Build Manual for Version 1, including how to connect it to a laptop or phone to generate the sound.

Adobe Portable Document Format - 3.59 MB - 05/09/2019 at 09:17

Preview
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DigiGurdy_electronic_hurdy-gurdy_keybox.zip

All files including .stl files for Version 1

x-zip-compressed - 6.86 MB - 05/09/2019 at 09:16

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  • Experiments to simulate a crank handle

    XenonJohn07/08/2019 at 11:09 0 comments

    Having finally worked out how to play the buzzing rhythm sound from the soundfont file on the attached mobile phone MIDI player, at present by pressing a button on the handle, this means I can now replace this button in theory at least with some form of crank handle.

    The crank handle is low cost and intended for a fishing reel. I have attached it to a motor which has a reduction gearbox. I had to buy 3 motors with different reduction ratios before I found one with the right amount of mechanical resistance to turning. In this video update I show each motor and also show how I can make an attached pager motor buzz by turning the crank. As the handle on the current Digi-gurdy can slide fully out and is attached electronically to the main body via a headphone plug, this means it could possibly be replaced by a crank module with no modification of the main body of the device, for those who wish to try it. More work required here but clearly this has potential. I will see how I get on and show the results in the next update.

  • Setting up Digi-gurdy with drones & rhythm buzz via a mobile phone

    XenonJohn07/08/2019 at 11:00 0 comments

    Update 08/07/2019

    Setting up the Digi-Gurdy to play via a mobile phone. 

    I have now worked out how to play the melody via Channel 1 of a MIDI player running on a phone, the High D trompette via Channel 2, a Low G drone via Channel 3 and the crank-activated buzzing rhythm sound via Channel 4.

    The MIDI player is free and called FluidSynth. The soundfont file (a library of sound effectively) that it uses is from the open source MIDI-gurdy project https://github.com/midigurdy/midigurdy to which I have added an extra buzzing sound.

    By pressing the upper green button on the handle, the device behaves as if you are turning the crank handle, i.e. you get the drone sounds you have set up plus the open melody string (G4). You then play the melody via the keys while the drones continue to sound. 

    In this version, the lower yellow button on the handle activates the buzzing trompette sound which is the rhythm section of a hurdygurdy, normally produced by momentary increases in rotation speed of the crank handle.

    This means, in my next update, I can look at ways to simulate the crank handle by generation of a suitable voltage signal to the Arduino Teensy via a geared motor to which a crank handle has been attached.

    I have also included in the video two quick bursts of the device running in demonstration mode just for fun.

  • Hurdy gurdy basics & Digi-Gurdy physical design.

    XenonJohn05/24/2019 at 15:05 0 comments

    Here is a video outlining the main features of a hurdy gurdy, the instrument we are aiming to partially emulate with an electronic practice version.

    The Digi-Gurdy presents two challenges. The first is the physical design and the second will be the internal electronics. It must be compact, have keys with the same layout as a real hurdy gurdy and while looking good, must be potentially capable of manufacture at reasonable cost. Current experiments combine 3D printed parts which could ultimately be made of plastic in combination with a frame which includes aluminium extrusions. 

    - There are ongoing experiments in an attempt to simulate a crank handle but for now a rigid handle is provided for the right hand, which helps you stabilize the device on your lap while playing the keys with your left hand. This may end up being the best compromise.

    - This handle is a commercially available plastic pistol-grip handle for cameras. 

    - It has been fitted to an alloy bar which slides telescopically out of the body of the Digi-Gurdy. 

    - This keeps the device compact and portable.

    - The OLED screen has been relocated into the main body of the device to improve ruggedness.

    - The keys are no longer held in place by a small bolt through their tail ends but now reversibly snap into place. This will reduce assembly time and allow easy replacement if ever damaged.

    - The micro switches for each key also now push-fit into their sockets without requiring glue to hold them in place. I am now also using roller switches as they give a great feel to the key action.

    - I could use resistance wire, contacted by the keys, or a ribbon potentiometer. This would reduce the quantity of wiring, however microswitches will probably be more reliable after heavy use, are designed to operate many thousands of times, give a good feel on each keypress and also return the keys well to their start positions after being pressed.

    The video below outlines the main aspects of the physical design. The electronics will be the subject of future updates.

    Here are the main parts laid out on the bench.

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Discussions

XenonJohn wrote 2 days ago point

Bear in mind that there is a learning curve with 3D printers and it is worth printing a few things that do not matter to you very much just so you become familiar with your particular machine. One or two of the very low cost ones out there are now pretty good.

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Jack Walsh wrote 2 days ago point

I was just putting together the main body of my digi-gurdy and noticed that there are apparently new print files for redesigned parts.  When will these be released?  I'm willing to start over!!  I particularly like the new key design -- the screws through the keys always seemed unworthy.  Thanks for all your work!!!!!

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XenonJohn wrote 2 days ago point

If you can wait a few weeks I will soon have a lot more free time to really finish this off. On expert advice (Nigel Eaton) I have been encouraged to really try to get a working crank handle simulator completed as part of this project. This will mean the 3D files might change yet again. Crank work will be feature of next update, more parts on order right now.

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Jack Walsh wrote a day ago point

Yay!!  Gives me some time to practice with just the keys!!!

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Shannon wrote 07/05/2019 at 17:53 point

This project might well be the one that makes me buy a 3D printer. I'd still save money over buying an acoustic hurdy gurdy.

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