A new vanishing point question... at least I think it is.

[MikeH]

I've been wanting to tackle a vanishing point for a while now; I really like the zvex 'seek' type pedals I have, and I'd really like to one up them DIY-wise.

So here's my thought:

Ok, well my original thought was to have a vanishing point tied to a 3 way switch that switched between 3 different LDRs in 3 different effects, so I could select between wah, or trem, or whatever.

But then I thought 'Hey... what if I could have one vanishing point driving 3 different sets of pots?'  Then I could have 3 different effects, but they'd all be sync'd up, using the same rate control and reset point.  So I could combine the different effects based on an output level for each; like a gentle treming in sequence with the wah, or vice versa, or whatever.  I think it could yield some really interesting results.

Question 1- Is this even possible? 
Question 2- If yes, is it feasable?

Perhaps I need 3 separate vanishing point circuits that can be syncronized somehow?

[RonaldB]

You can make one clock driver for 3 4017 chips. That way you have the rate set for all 3 4017 chips.
You could use a simple 555 timer as a clock or a 40106.

[MikeH]

Thanks for the reply-

I see... the vanishing point uses a 4093 as a clock driver.  Would it be as simple as connecting the same clock driver output (I guess that's what you'd call it?) to 3 different 4017s?

This type of thing, btw, is COMPLETELY new to me.  I read the vanishing point article, and I understand how it works, but I'm a little lost on how to make it do anything else.  I'd have no idea how to do the same thing with a 555 or 40106.  Any info would be appreciated.

Also:  I'd like to be able to keep the 'random' ability- I think thats why he selected the 4093, right?

[The Tone God]

The 4093 is used so there are enough logic gates to do the random stuff. I have been lightly working on another random mode that might be easier and more consistent for people to build but thats another thread/article.

Anyway, back to your main question. Yes you can run more then one effect off of the circuit. I would not bother with having multiple 4017. You can have trouble syncing all of them in the random mode. I would instead stick with a single 4017 and build a LED driver array off of the 4017 outputs. This can be done with transistors or logic gates.

Andrew

[MikeH]

The 4093 is used so there are enough logic gates to do the random stuff. I have been lightly working on another random mode that might be easier and more consistent for people to build but thats another thread/article.

Anyway, back to your main question. Yes you can run more then one effect off of the circuit. I would not bother with having multiple 4017. You can have trouble syncing all of them in the random mode. I would instead stick with a single 4017 and build a LED driver array off of the 4017 outputs. This can be done with transistors or logic gates.

Andrew

Hmmm... so if I were running 3 effects, each 'stage' on the 4017 would drive 3 different LED/potentiometer combos? And I would need some sort of LED driver to do this?  Would that be just to have enough voltage being sent to each set?  I'm a little confused, but I think I understand what you're saying.

Although- if I had a different 4017 for each effect, then could I adjust the number of stages each one runs differently?  IOW, I could have a trem running 9 stages and a wah running 10 stages, and theoretically it could cycle 900 times before the same combination occurred again?  That would be cool.

[The Tone God]

Hmmm... so if I were running 3 effects, each 'stage' on the 4017 would drive 3 different LED/potentiometer combos? And I would need some sort of LED driver to do this?  Would that be just to have enough voltage being sent to each set?  I'm a little confused, but I think I understand what you're saying.

I believe that is what you were asking for meaning the same stage selected but with a different pot for each effect. The 4017 does not have enough current driving ability to drive the four LEDs (one for the stage indicator and one for each of the three effect's optocoupler) so you need some driver for the LEDs.

Although- if I had a different 4017 for each effect, then could I adjust the number of stages each one runs differently?  IOW, I could have a trem running 9 stages and a wah running 10 stages, and theoretically it could cycle 900 times before the same combination occurred again?  That would be cool.

Then you are looking at building three VPs each on their own I guess.

Andrew

[MikeH]

[MikeH]

A question about pot selection; I read through a search that pot selection depends on what type of LEDs you're using- what about the LDR you're using to drive the effect?  I'd imagine that would play in a lot as well.  So, let's say I have an effect that uses a 1M pot- Ideally I'd like to find an opto with a dark resistance around 1M.  Surely that will need to be fed a different voltage than one with s dark resistance of 100K, right?  Or is it all about the photocell, not so much about the LED inside?

[jakehop]

Hi Mike,

Most LDR's work within their range, at "no light" as opposed to "full light". That is, one LDR might be 100ohm / 1M ohm and one might be 50ohm / 100K ohm.

Hope this helps. This is very exciting.

Kind regards, Jake

[MikeH]

Hi Mike,

Most LDR's work within their range, at "no light" as opposed to "full light". That is, one LDR might be 100ohm / 1M ohm and one might be 50ohm / 100K ohm.

Hope this helps. This is very exciting.

Kind regards, Jake

Yeah... um, I don't really "understand" how LDRs work... so uh, yeah... I've got a little research to do in that dept.  The only time I've ever used one was in the tremulus lune, and all the values were selected for me, so I didn't have to figure anything out.

[The Tone God]

Well ideally you want the same values, yes but often those quoted values apply when using the parts in their value range and they still drift so it can still can be difficult. Luckily it sounds like in most of the application you are planning to use them with you could get away with the variance.

Andrew