Re: Solenoid Actuator?


Rich Grise wrote:
On Tue, 04 Jul 2006 11:12:51 -0700, mtowns wrote:

I am trying to actuate a metal rod to move with certain different
velocities. I am hoping to use a solenoid and a velocity-sensing
feedback system. The output should be appropriate for pusing a
weighted piano key. Is this feasable? Are soleniod actuators avaliable
pre-assembled, or would I have to make one myself? Thanks.

Find an amusement machine vendor in your area who still does pinball
machines, and get some drop target reset solenoids. I used to work
repairing pinball machines (and juke boxes, Pac-Man, and so on - kewl
job!), and was tempted to use them in a piano project of my own, which
never materialized. (sigh)

If you've ever played pinball, you've seen drop targets reset - the
stroke is maybe 1-1/2", and they don't have a lot of force (they raise
those little plastic targets, which latch in place), but by eyeball
and gut feeling, they looked like they'd be ideal. You'd have to
carefully control the current, to give the attack and sustain that
you want, of course.

The throw on a piano key is about 9mm - 3/8 of an inch.

To simulate the force that is required to accelerate the hammers at a
5:1 mechanical advantage, you need to develop forces of the order of 20
Newton (about five pounds weight).

Modeling the 14-19 moving parts between the key and the hammer seems to
be a fairly important part of the job - carefully controlling the
current to do that is quite tricky.

Brent Gillespie's Touchback Keyboard project is described in the
literature - I posted a couple of URL's earlier in the thread - and
level of simulation required seems to eat up quite a lot of computing
power.

--
Bill Sloman, Nijmegen

.

Relevant Pages

  • Re: Solenoid Actuator?
    ... velocities. ... I am hoping to use a solenoid and a velocity-sensing ... weighted piano key. ... and get some drop target reset solenoids. ...
    (sci.electronics.design)
  • Re: Solenoid Actuator?
    ... feedback system. ... weighted piano key. ... and velocities you get when you strike a piano key, ...
    (sci.electronics.design)
  • Re: High-force Push Solenoid
    ... mtowns wrote: ... I am looking for a push solenoid capable of pushing at about 5 kg. ... Stroke may be a problem too...you will need 10 odd mm to operate a piano key no? ... And use steel cases to provide a magnetic circuit...the end cap is important in hold applications, but if you are going for a linear force adjustment via current control it may not be needed ...
    (comp.robotics.misc)