How to Wire Keyboard to 555 Timer?

[samp]

Hi,

I have recently ripped the keyboard out of an old Kawai organ and would like to use it as a part of this circuit (see attached).

I understand how this circuit is played with a stylus from the 555's pin 3 out, but am having trouble replacing this with the organ keyboard (see photos). I've tried connecting the bus (green wire?) to pin 3 and a single key's wire to pin 2, but with no results.

Is this something to do with CV?

Any suggested schematics/links would be appreciated.

Thanks,
Sam

---

001.PNG
Description:
Filesize:	675.47 KB
Viewed:	682 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

---

---

01.jpg
Description:
Filesize:	149.5 KB
Viewed:	558 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

---

---

02.jpg
Description:
Filesize:	163.23 KB
Viewed:	527 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

---

[MusicMan11712]

[removed for personal reasons]

[gdavis]

Did you meter the keyboard to see if it actually works the way you think?

Assuming it actually connects one wire for each key to a bus wire, you'd need to connect the key wire to is corresponding pad in your circuit instead of pin two. Each pad creates a different resistance between pins 2 and 3 which controls the pitch. Connecting it directly to pin 2 eliminates all the resistance so the pitch is probably above the audible range.

[samp]

Thanks for your help! I'll have a look.

[Cfish]

That is the exact circuit that got me really interested about 7 years ago. I did the same thing you are doing. I used an organ keybed that happened to be single buss. I was lucky enough to have an easy keybed to use. I just had to place a resistor between each corisponding key wire. Basicly make the keys be wired like the key and stylus section of your schematic. Stylus wire ties to the buss of the keybed.

Only problem is if you hit 2 keys

I had the forethought to use 100 ohm 1% resistors in the resistor chain, because that was what every volt per octave keyboard circuit I could find used.
It does not tune this circuit correctly. However
The keybed I use to control my home built modular synth is that exact . Keyboard and resistor chain setup I built for this project back then.

Is a thread on here called easy analog synth project. That was sort of the next step after this project. Was a lot more musically usable. I still use that project in one of my bass pedal sets

---

IMG_0525.JPG
Description:
Filesize:	1.59 MB
Viewed:	536 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

---

[samp]

Woo! Got it working! Thanks Cfish -nice synth by the way.

Turns out the first two keys I was testing are broken.

Definitely going to try the bass pedals next.