stylophone mod

[Happy Harry]

Hi Dave

inline:


>From: Dave Krooshof <krooshof at xs4all.nl>
>To: synth-diy at node12b53.a2000.nl
>Subject: stylophone mod
>Date: Mon, 8 Jan 2001 17:05:48 +0100
>
>So.
>I bought a stylophone. It's a little organ that uses a pen to close the
>circuit, rather then a bunch of real switches. The print is visible through
>a hole in the box, and on it is a grafic representation of a pianokeyboard,
>in metal, some 12 cm wide for 1.5 oktave. Toughing the keys with a pen does
>the trick.
>NB: Between all keyfields and the pen, the 9 volt batterypower is here. So
>the actual keyingcircuit is not a standard resistorbank. Or am I wrong?

Correct... it is digital AFAIK.
>
>As it is far from a synthesizer, I feel like needing a few modifications.
>
>0. The frequency down with 1 or even 2 okatves. It will probably mean
>cutting out a R and solder a pot in somewhere.

Probably find the audio signal and use a digital divider, CD4013
or my favorite the CD4520. Maybe even make a mixer to combine outputs.
>
>1. Portamento.
>Sliding the pen over the keys does: plidididididoo. I need it to do 
>pliiiiioo.
>So I figure I need a capacitor somewhere, to hold the CV for a while.

I don't think so. Probably you will NOT get portamento, unless you
use a PLL  (CD4046) I think Scott Gravenhorst is the resident guru here...

>If the side effect is that every note will go down after release: Exellent.
>I'll make a not-holding switch for it.
>Any hints on where I will want the cap and what the value could be?
>
>2. a frequency wheel/knob.
>So far, I noticed that if I switch the device off while playing, it nicely
>drops in tone. Good. So to safe these old components, I want to find a spot
>that a) does drop the frequency, but does not hurt the electronics. Any
>hints?

Probably dropping the voltage is affecting oscillator speed... probably a 
top octave generator chip of some type...
Find and modify... ;^)
>
>3. Dirt
>So, back in the tough the electronics topic!
>I definitely need some dirt in this machine. Toughing the keys lightly does
>sound dirty already, as it's switching on and off all the time (noise
>modulation).
>Any ideas?

If you make the octave divider suggested, use some exclusive or gates
to combine outputs. Check out the "Walsh Functions" (list guru please
speak up here...). I did this on an old monophonic casio... all the
grit you want !!!

Stylophone... pretty unusual choice...
You might also P/V convert the output (See xavax.com/efm PV-1 for
details... ) and drive a standard VCO. OTOH then why not pitch the
stylophone and build a synth... ;^)

H^)  harry
>
>
>Dave -stylophone newbie- krooshof
>
>--------------------------------------------
>Dave Krooshof http://www.xs4all.nl/~krooshof
>geluidstechnicus @ http://www.ahk.nl/the/theatertechniek_ov.html
>webmaster: http://www.popronde.nl
>-------------------------------------------
>no html mail please
>
>

_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com