3-potentiometer based, high brightness led loop-fade in/out circuit

Hey there, nice to meet you.

I've tried to build a circuit to perform fade in - hold - fade out loops. Now i have this challenge to insert 3 potentiometers to control time loop lenght, maximum brightness and hold time each pot. Trouble for me is to resolve need for long RC time constant when the 2 other potentiometer are controlling different parameters.

I've created a time-intensity chart to explain what am I talking about.

the loop time goes from 5 seconds to 20 secs, i guess it is enough to create an off time effect long enough to be noticed

I've assumed that the brightness potentiometer also defines number of HB leds in circuit.

thanks
the real proyect involves many colors for sculpture lightning...also controls fountains pumps relays to be sequenced via MIDI with music!!!

Hi. I'm not sure I fully understood your request.

Is it very important that the curve is sinus shaped?
Is your project based on µPC?

How many LEDs and what current? You want to adjust brightness and be able to switch more on to increase brightness? If so how how many steps?

curve is standard capacitor based, it has no need for special algebraic shape... project is 100% analogue!... led number might vary but i left it out of core circuit because of the color change for each circuit i plan to build... switching is a good idea but it is also left it out of core circuit... high brightness leds have this versatility with simple resistance potentiometers...

Not exact that curve anyway

If curve is based on a RC pair, then the curwe won't look like your drawing anyway. It will look more like this (see atached picture).

It may be possible to produce round curve using integrators and differensiators combined with adjustable current mirrors. But I haven't any thaughts on how to make it that way.

After reading your post again I think what you are after is called a color organ. Try a google and let us know if that isn't what you are after.

What about using a 556 timer pair? One pot controls a short time based unit that is the intensity adjustment (pulse width modulated intensity) and the other the on time. You should be able to get some interesting effects by letting one timer control the duty cycle of the other.

yeah I know... RC curves fade out that way...perfect!... color organ looks expensive... yes I tried 555 pair... the only problem was to open and tighten hold time inside the RC curve... so inside this curve there is the upper crest that is intended to be prolonged... the 555 pair looks fine

Ramp Circuit

See if this concept is about what you are looking for.

amazing!
if I use a universal power converter will it handle circuit as a a separated environment?

thanks!

Be aware, it will only run 1 or 2 leds before the power is to high.