SV: Re: [sdiy] Keyboard Encoder Experiments...

[karl dalen]

You can multiplex LVDT's synchronous detectors.
KD

--- Jim Patchell <patchell at cox.net> skrev:

> Each LVDT will need an amplifier and a synchronous detector (ok...real 
> simple...just an analog switch that toggles an amplifer from a gain of 
> +1 to -1 synchronized with the signal).  Should be able to do that with 
> a quad opamp (per key) and an analog switch.  Probably about $3 worth of 
> parts for each key.
> 
> The AD converter I plan to use is a tlc2551 which only costs $9 in ones 
> (12 bits) and converts at 400KHz.  I will mux that between all the keys 
> for an overall sample rate of about 5KHz per key.  The digital 
> electronics will be an FPGA...(about $10), and an AVR ($12).
> 
> -Jim
> 
> Ben Stuyts wrote:
> > Hi Jim,
> > 
> > On 11 Feb 2008, at 20:50, Jim Patchell wrote:
> > 
> >> http://www.noniandjim.com/Jim/KeyboardEncoder/KeyboardEncoder.html
> > 
> > Looks great! And if you go away from 'conventional' keys, you could even 
> > build something lake the Haken Continuum keyboard 
> > <http://www.hakenaudio.com/Continuum/>. I think this 
> > <http://www.google.com/patents?vid=USPAT6703552> is the patent.
> > 
> > I've looked a bit at (commercial) LVDT's for the company I work for, but 
> > cost was, as you said, always prohibitive. But wouldn't this need a lot 
> > of electronics? AD has some LVDT amplifiers, but these are expensive (> 
> > $15) too.
> > 
> > How about hall-effect sensors?
> > 
> > With kind regards,
> > Ben
> > 
> > 
> > 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



      __________________________________________________________
Ta semester! - sök efter resor hos Yahoo! Shopping.
Jämför pris på flygbiljetter och hotellrum här:
http://shopping.yahoo.se/c-169901-resor-biljetter.html?partnerId=96914052