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  3. Fitted basic optical encode circuit to my , now figuring out optimal settings for calculating wheel speed. Notes:

    Sane gurdy speed of 14 revs every 10 seconds = 1.4 RPS
52 markers on wheel = 52 * 1.4 = 72.8 transitions per second ≈ 73Hz minimal input signal

Timer nominal input freq is Fosc / 4 = 4MHz / 4 = 1Mhz
Max prescaling = 1:256, i.e. TMR0 increments once for every 256 Fosc/4 pulses
Resultant timer freq = 1Mhz / 256 = 0.00390625 Mhz = 3906.25 Hz

Input signal has ≈50% duty cycle so periods between pulses should be 1 / 73 = 13.69863014ms

Period of 3906.25Hz wave = 0.256ms
Num pulses @ 3906.25Hz after 13.7ms = 13.7 / 0.256 = 53.515625

1.4 RPS is minimal normal gurdy trompette playing speed, so counting 54 clicks per transition gives a little space for speeding up and a lot of space for slowing down.

High gurdy trompetting speed of 24 revs per 10 seconds = 2.4 RPS
TPS = 52 * 2.4 ≈ 124.8 = 125Hz maximum input signal = wavelength of 1 / 125 = 8ms
Num pulses @ 3906.25Hz after 8ms = 8 / 0.256 = 31.25

    So these values should give a just-wide-enough span of ≈20 ticks between nominal and trompetting speed, with room to halve or potentially even quarter the prescaler if this turns out to not be enough. One advantage of these values is space to track much slower wheel movements, opening this up to be used for slower performance tools as well as speed measuring.

    An external switch could always adjust the prescaler if necessary to cover both use cases.

  5. ↪ Sophie Dennis: @BarnabyWalters I mistook part of the handwritten notes for "disco" - an extreme example of varying tune for different dance types :)

    @sophiedennis haha yeah “dissociation” is the French word for trompette rhythms to go with the melody, abbreviated to “disso”. But if anyone could do disco gurdy, it’s Gregory Jolivet ;)

  10. Sad news about the George Sand committee on rencontresdeluthiers.org — I don’t know exactly what this means for Chateau d’Ars but I’m assuming it’s either not going to continue, or will continue in a diminished form.

    Attending for the first time last year was one of the most intense and enjoyable trips I’ve ever been on, filled with wonderful instruments, music and even more amazing people. Whatever happens to the festival, those things will remain.

  11. Reflecting on 2013 with my . Biggest things personally have been making my second , moving to Iceland and meeting+working with all the great people over here. Lots of and progress, including a great indiewebcamp in September.

    Looking forward to 2014: more cooking, more indieweb progress, seeing more of Iceland, going to some gurdy festivals, improving hardware hacking abilities, connecting my gurdy and other devices to the web and each other.

  12. Project for Chateau d’Ars (and maybe Halsway) in 2014: fit gurdy with wheel speed measuring device, record traces of different peoples’ trompette styles.

  14. Feedback Loops

    The larger the gap between one major feedback loop and the next largest of any given stage of an activity, the more assumptions must be made about that stage.

    Example: planing a hurdy gurdy top to thickness.

    Tasks, feedback loops in order of duration (timings are approximate from memory):

    • Every millimetre of planed wood, ≈150ms audible and physical feedback
    • Every ≈1cm of planed wood, ≈500ms visual feedback loop seeing the shavings protrude from the plane (or not, which is equally valuable)
    • Every ≈10cm of planed wood, ≈3s visual+physical+audible feedback loop of one complete shaving detaching
    • Every ≈20cm of planed wood, ≈5s visual feedback loop seeing freshly planed surface, erosion of pencil marks
    • Pause every ≈10 plane strokes, ≈20s physical feedback loop picking up the top and flexing
    • Pause every ≈20 plane strokes, ≈1 minute precision visual feedback from re-measuring the thickness of the top with a caliper

    The gaps between feedback loops become larger as the durations become larger, as do the assumptions which are made about the task at each level until the next feedback loop arrives. I suspect that experience level also affects both the value gained from each feedback loop, increasing the actor’s knowledge of the system and increasing the amount of time which can safely be left (i.e. the amount of assumption which is safe) before more feedback is required.

    Two observations: the existence of vastly longer feedback loops of experience accumulating which affect the shape of existing loops, and that the smallest feedback loops are broadcast by the environment (audible feedback, physical resistance) but longer ones require active participation (testing the system).

  15. Recorded an unnamed tune yesterday + saw for the first time today = easy tune name! Lights In The Sky:

    Want to play it? Have a peek at the sheet music.

  16. Rediscovered my love of sewing whilst modifying a guitar strap to work with my , now desperately wanting to make something with fish leather.

    btw, best place to get needle+thread in Reykjavik 101 is the art supplies shop on Skólavörðastigúr — Tiger sells needles cheaper but no thread (wat)

  18. I need some musical help! What time signature is this clip in? It’s been rolling around in my head for the past three weeks but I can’t figure it out.

    
K:Amin
AB cd- dc _ed cd cB cd |fe de- ec2 AB cA _ed cd :|

    The problem seems to be around the 19-20th notes — that’s how I play it but it means there’s an extra quaver. Otherwise it could almost be alternating bars of 7/4 and 8/4. Any ideas?