Home made CV+Gate

[SuperKoopa]

Just a pic of the idea;
this sould be the simpliest way to build a CV-gate controller.I've read somewhere that 8mm video tape is a good resistor so we can use this like a potentiometer for a home made CV controller (watch the pic)

From the original schematics we can see that S1 is connected to ground when pressed.Probably (don't do it until we are shure of this!) touching Pin 2 of S1 we can put to ground it!
OK the picture is more esplicative.

Important: maybe there are some problems with static electricity(the same that could burn ICs) .We can avoid this using a zener diode protection like that used for CV inputs.

Please tell me if it could be danger (or useless) for the SL.

---

CV.GIF
Description:
Filesize:	5.44 KB
Viewed:	15313 Time(s)

---

[dnny]

on the web i have seen these ribbon controller instructions:


and more advanced:



but there is no gate option on these but your "touch the ground" - idea will be perfect to generate the gate. so if we combine these whit your design i think it will work on SL whit out frying it. but in any case the 9.1V zener is not a bad idea at all to protect SL CV inputs

or if you are planning on something more complicated you can make this board and include keyboard and ribbon controller to the keyboard bus input. and for all you looking for descent power supply this board has a +/-12V PSU included! so you can power up all those modules - and SL

[SuperKoopa]

The Simpliest idea for the single bus keyboard (With any else but the bus, resistors and switches ) is to put two switches for each key or a dpst switch for each key.One is for CV the other simply put to ground the pin 2 of S1.
In this way will be lost portamento legato ... ,but I think that this is the simpliest and better way to build a keyboard controller.

[Clack]

if you have some lying around anti-static bags work ( ive found all the ones with low enough resistance are genrally black ones )

[Macaba]

To further the point about anti-static bags, its the ones that are a black non-seethrough plastic that are best, NOT the silvery see-thro ones.

EDIT: To further my further point, the black bags are matt in appearance. You should know exactly what i'm talking about now.

[SuperKoopa]

Sorry I've made a big mistake

touching pin2 of S1 we will not put this point to ground directly,but via a 50k-200k resistor (this is the typical resistance of an human body).I don't know what this really implies but I think that in this way we don't put to 0V pin2.(Is this true?)

One suggestion may be a glove with a piece of conductive material glued on the top of a finger,connected directly to the SL ground.

maybe it isn't a powerful and free control but it's so '80s !

[v-un-v]

The ribbon controller is a nice idea, but how about a cheapo Ondes Martenot manual? Ideally this should be made with wire (for the tension needed), but I used some string, just to demonstrate the point (unfortunately string is crap- so it doesen't work very well as it stands here!!).

I reckon this could work well with 10 or more multi-turn pots (as there just aint enough travel on these shitty pots). One could also write a scale on (in this case a floorboard off-cut) the wood for easy playing.

There are also 2 pots. One is a dummy. Notice the cotton reels! (ingenious eh?;). These are held to the pot shafts with rubber-bands.

Next I will make a wobbly keyboard!! -But not until I finally finish my SoundLab which is taking ages.

Food for thought anyway.

Tom

---

ondes-over.jpg
Description:
Filesize:	55.56 KB
Viewed:	15222 Time(s)

---

[v-un-v]

.....and the underside.....

---

ondes-under.jpg
Description:
Filesize:	54.01 KB
Viewed:	15220 Time(s)

---

[mosc]

What keeps the tension?

[v-un-v]

[v-un-v]

a continuous loop? that would do it- wouldn't it?

[Macaba]

Loop is the best idea, with a return line basically.

[SuperKoopa]

This is more difficult to built and is fragile but should work!

---

CV 2.GIF
Description:
Filesize:	6.51 KB
Viewed:	15181 Time(s)

---

[Scirocco]

I´m trying to buid the ribbon controler without any success at the moment.
I´ve been using 8mm and VHS video tape but it seems to have a really-low conductance
I´ve used 1/4 " audio tape from my old akai reel-to-reel too and it works ,but not fine,too much resistance (about 10M in about 2" or 5 cm. +/-)
I´ll have some 1/2" audio tape soon and I´ll it with anti-static bags to see wich´s better material .
Anyone has some pics of a well done ribbon

[Scott Stites]

An alternate type of conductive material may be that strap material that is used with the little webbings one wears on one's feet in order to dissipate a charge through conductive flooring.

Check out the late Larry Hendry's site here:

http://www.wiseguysynth.com/larry/ribbon/ribbon.htm

Cheers,
Scott

[Uncle Krunkus]

Another thing worth checking out is the black foam they use for storing static sensitive chips. I've tested this and it works. If you could get a long enough piece, it would just be a case of deciding how wide (and therefore how much R per centimetre) you want to cut it. You could even cut a tapering piece and get a log "strip" I suppose.

[Scirocco]

Ty very much, really cool link, and I´ll take a look at that black foam to see what happen...

[Scott Stites]

Tom Henry's Percussion book has a section that details making drum pad trigger sensors out of the conductive foam (placing it between two blank copper PCB's).

I don't know if they've changed the makeup of that stuff since then, but I do know in the past the black foam, over time, has been know to degenerate into a nasty black goo. I've got some IC's that were put in that stuff in the late 80's that wound up with gooey legs as a result. Maybe it's improved since then.

Cheers,
Scott

[Uncle Krunkus]

You can scrub it off with "Servisol" or a similar hydrocarbon cleaning solvent. Isopropyl alcohol would probably do it too.
The foam I've got is brand new, so I don't know how it will age.