[sdiy] voltage controlled monostable?

[fmg]

Sorry if not posting this before, I was computer-off these days
because I'm working in a similar project.

I'm building a 4017 based variable-step sequencer and (though
having 4017s and inverters) it's mostly analog.

The principle is simple, based in RC timings and comparators with
a pot in the R part. This let me set the duration of each step
individually in the 100ms...15s range.
My design has 16 steps and I'm currently working in some details
as a master "speed" pot and cascade capabilities.

I think it's a promising project cause its simple, cheap and (perhaps)
could be useful for someone in this crazy community.

Once finished I'll post a clean schematic somewhere in the net.

Fabio Gonzalez


Michael Ruberto wrote:
> 
> I was thinking about building some very complicated logic thing with BCD
> switches, Shift registers, binary counters, magnitude comparators and a PLL
> in order to have a gate sequencer where each step could have a variable gate
> length. now on paper the design seems sound and probably would have worked
> until I thought about the cost of putting BCD switches on each stage - alot
> of money!!!
> so there has to be a cheaper way to do it...
> 
> I think it could be done pretty easily by making a few changes to a VCO.
> take a basic VCO and use an external clock trigger to reset the timing cap.
> then have a comparator to generate the output. you would be able to obtain a
> gate of any duration by changing the pitch CV. in the Gate sequencer there
> could be a row of voltage divider pots that sum their outputs into the pitch
> CV input. has anybody here built such a device?
> 
> Mike
> 
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