The future?

[henry]

Is this the beginning of software copedents?!




http://hackaday.com/2014/07/09/servoben ... dal-steel/

[Will C]

I got involved in a lot of discussions, and considerable amount of initial design work, back in 2009-10. But my design was far better. Select any copedent on the fly. Colour touch LCD screen user interface. The servos were more sophisticated. I'm surprised he got away with using RC servos, if that's what they are, the jitter on them is horrific. But this particular video, or one very like it, has been doing the rounds for a good while now.

The idea is a winner. It will happen, if the commercial returns can be good enough. But there is massive (emotional) resistance to eliminating the mechanical linkage between pedal and changer finger. Why, I don't know. Goodbye to temperature effects, and mechanical slop. Hello to flexibility, ever-accurate tuning and copedents not achievable with today's changers. I never saw one scrap of reasoned debate about it from the naysayers, and a lot of nonsensical knee-jerk stuff about guitars playing themselves. There's none so blind as them that won't see.

[henry]

wow! what happened to your project?
have you got any designs I can look at? just interested in what the changer would look like if it was servo controlled

I was just interested in this cos the guy was actually getting some good sounds out of it..

[Will C]

I didn't build much Henry, just basic explorations into certain types of sensor and their suitability to the role, feasibility studies, basic mechanical and electrical design sketches. For instance: the changer is very close to the pickup. I was looking at motor-driven servos to position the changer fingers - to vary the string tension. Motors generate magnetic "noise" which I thought could be picked up by the pickup, so I designed for the power supply and servos at the left end of the string, well away from the pickup, with tuning at the right - exactly the opposite of a conventional steel.

I needed to be sure that I could position the changer fingers accurately enough to pitch the strings and their bends correctly, which led back to needing a certain basic resolution or ability to measure. That got me experimenting with Hall-type proximity sensors and phase-sensitive linear differential transformers as the position sensors for the changer. Hall effect devices are simple, but hugely non-linear, so after much experimenting on efforts to linearise their response by having a uniform magnetic field gradient, I tried the LVDT instead, which works on a timing-based approach. This is easy to do digitally, as modern single-chip controllers have multiple timers built in.

I even looked at remote sensing of the pedals, with short range "Bluetooth" style radio linking of the signals derived from pedal position.

And so it went on. The bottom line was "it has to be possible to minimise the mechanical engineering content, because electronics can be mass-produced cheaper than mechanical parts". All of the work I did assumed the strings wouldn't expand or contract with temperature change, a bit simplistic. So I realised I needed another approach, measuring the pitch of the notes in each string so as to rule out that effect. It was the difference between closed loop and open loop control. That required further work. So I stopped work after about 18 months, because I decided I didn't have the resources to see it through - I preferred to spend what leisure time I had on practising the steel rather than trying to re-engineer it! It was fascinating, but I'm only one guy, and I have so many calls on my time so it will have to be seen through by a team in my view.

[henry]

well what small amount of that that I understood sounded very interesting and impressive!

are you saying it would be self-tuning too?!

[mick hearn]

Whilst this is a brilliant idea I am sure it will not replace the steel guitar. At the end of the day its just another guitar with pedals. Burns came out with the idea of pedals pulling cables in the sixties and that was coupled with other players looking at palm pedals, b benders and so on. It will appeal to a limited audience. There is nothing that will replace the pedal steel. Last year I was going to buy a Duesenberg Pomona 6 but instead spent the money on a ShoBud S10. Now which do you think won hands down?