Cool Cicuit to Add Wierdness to LDR-Based Pedals

[erix]

I saw this one in December "Nuts-n-Volts" mag. It simulates a flickering candle with a single LED.
A constantly varying voltage is supplied to the LED by four oscillators built from a single 4093, each running at different speeds.
The article showed fixed resistors controlling the freq. (1M, 470k, 270k, 100k for 1Hz, 2Hz, 4Hz, and 10Hz respectively) but I drew them as variable.

R18 biases the LED so it never goes completely dark, should probably be a pot labeled "Sensitivity"

I imagine you might be able to get that cool Johnny Marr Tremolo thing happening with all four oscillators running almost the same freq.?

Thoughts?

[nelson]

Looks cool, is it square wave though?


EDIT: looking at the datasheet it is a squarewave.

[birt]

so if you put this on an idiot wah you can get a crazy idiot wah?

[slacker]

so if you put this on an idiot wah you can get a crazy idiot wah?

probably yeah, I've added something similar to my uglyface (which I'll be posting about soon )and you get some pretty good noises, kind of like a sample and hold filter. There's an article on GEO about this sort of random LFO, or have a look at Ken Stone's psycho LFO over at http://www.cgs.synth.net/, it's in the modules section.

[petemoore]

  Well yes, that'd be cool.
  I'd typed about dual LFO, series or parallel, [to get away from the ~ normal sweep waveshapes into something less repetetive].
  "Series">One LFO controlling the speed of the other LFO, making it's cycling accellerate/deaccelerate.
  "Parallel"> Two LFO's at different rates powering 1 LED per LDR into peak brightness-es.
  "Parallel II" two LED's per LDR per phase stage, each bright/dark cycling happening at a different rate Via 2 LFO's...each phase stage would have 2 LED's 'blinking' at different rates and peak brightnesses, shining on 1 LDR...
  This circuit^ would do a similar job?...it looks like it could be capable of manipulating LDR Resistance in 'odd' ways...

[object88]

is it square wave though?

You could apply a gentle (3db/oct? 6db?) LPF to round it off to a triangle.