[sdiy] (simple) musique mechanique

[R. Drake]

bobby,

thanks for the details, & exciting to hear about your project.

have you heard/seen maxime rioux's "automates KI" system?  i picked up a cd
a couple weeks ago, and just copied this description off the web:

"maxime rioux (aka maxime de la rochefoucauld) will perform his great
'automates ki'. here's how they work....the automatons are activated by high
and low inaudible frequecies. those frequencies drive the membranes of
little woofers* on which a structure made out of sticks and springs is
attached. The structure hits acoustics instruments like drums, cymbals,
strings, bells, cans, etc. all the automatons are controlled individually by
an impulsion board. this impulsion board is like a traditionnal mixing board
but instead of an audio volume, it is the electrical power of the impulsion
given to the automatons which itself generates an acoustic sound. this
impulsion board has 24 faders which receive different impulsions and 24
outputs connected to an amplification tower. *some of the automatons are
activated by solenoids?."

besides the mechanical sound production, what i find interesting is the
actuation based on sound input... the CD is very pleasant, & musical, i'd
love to see it live.


also, if you're ever in the area, a trip to the DeBence Antique Music World
museum in Franklin PA is a must... incredible collection of automatic music
machines... an 2 hour's tour of the place consists of one of the old timers
walking you thru & turning each one on.

all best  
lbd



on 1/8/04 6:54 PM, Robert Pietrusko at bobby at csounds.com wrote:

> Hi List,
> 
> I'm going to try to stuff it all into one email. :)
> I'll try not to forget anything.
> 
> First off, Ken, yes I *love* all of the old automated
> instruments.... orchestrions and such.  musee
> mechanique stuff.  Goes back to riding merry-go-rounds
> as a kid.  There is a whole community that still deals
> in building those kinds of instruments, pneumatics and
> all, which I really respect. some of their websites
> are just insane.
> 
> 
> as far as mimicking a human drummer. I think that is
> really interesting but well beyond my knowledge.
> However, making Hurky-Jerky Robot Music?  I'm really
> into doing that! It is certainly nothing new but I
> just really like to build stuff and it's rewarding to
> hear it firing off like an uzi. :)
> 
> As far as the operation :  the "simple"  in the
> subject line is not self-deprecation but rather
> descriptive.  I've never worked with actuators before
> so I wanted to make this as simple as possible. Sorry
> I didn't take better pictures.  this probably shows
> the mechanism the best :
> http://www.enfason.com/cgi-bin/i/batonmaton/autoDrum041.JPG
> 
> 
> I'm using a linear pull-type 12v solenoid with a force
> of 128 oz.  at 1/8".  You'll notice on the solenoid
> arm is a compression spring.  basically,  the solenoid
> is constantly pulling on the stick and is thus
> compressing the spring.  when my logic goes high in my
> circuit (i.e. 'hit' ) the circuit cuts the current
> from the solenoid and the restoring force of the
> spring smacks the drum stick into the drum head,
> bounces off, the solenoid turns back on and once again
> compresses the spring.  I did some dynamics
> simulations in matlab to determine the location and
> geometry of all of the components, for maximum power
> delivered to the head, and to compute the spring
> constant and length.
> 
> Also,  the amount of time the solenoid is off is
> constant and was calculated to be less than the
> natural period of the spring so as to prevent
> oscillations, but long enough to allow the tip to meet
> the head and reflect off from natural force.
> 
> PWM  :  I agree that being able to control the
> velocity would be great and I thought about that for a
> bit, however PWM in this project is just a
> practicality.   The solenoid does not have an infinite
> 'on' time, and therefore needs to be constantly
> switched on and off.  enter PWM.  I found a duty cycle
> that would maximize the solenoid's 'off' time but
> still deliver enough current to overcome the force of
> the spring and hold it in compression.  Velocity
> control is an ultimate goal but for now, I had to
> start somewhere.
> 
> I chose this method because it seemed very simple and
> like Tim said, I liked the idea of not plowing a stick
> into the head of a drum with a solenoid. So instead, I
> let a spring's natural motion do all the work.  Also,
> this minimizes any delay in the control-- there is no
> 'cocking' that needs to be done because it is normally
> cocked.  I was worried that the result would sound
> whimpy but it is actually quite loud.
> 
> 
> If anyone has that Nuts & Volts article Michael
> mentioned I'd love to read it. It would be a huge help
> as I haven't touched a PIC in about 2 years, much to
> my chagrin.  Time to print out that 300 page pdf PIC
> document.  Say, does anyone have a friend at kinkos?
> ;)
> 
> 
> I'll keep you guys posted.  and by 'posted' I mean
> I'll be asking midi PIC questions.  Consider
> yourselves warned!
> 
> -bobby.
>