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Candle Flicker LEDs

Posted: Thu Jun 23, 2011 9:04 am
by oldangelmidnight
So what can we do with these: http://evilmadscience.com/productsmenu/ ... 89-candled

Can we make a flickering tremolo?

Re: Candle Flicker LEDs

Posted: Thu Jun 23, 2011 9:42 am
by culturejam
I've thought about this in the past. Not sure if they are suitable for audio use, as they may introduce noise from the integrated circuit that creates the flicker.

Re: Candle Flicker LEDs

Posted: Thu Jun 23, 2011 10:40 am
by oldangelmidnight
Is there a simple, commercially-available pcb that would work to try it out?

Re: Candle Flicker LEDs

Posted: Thu Jun 23, 2011 11:22 am
by culturejam
I should think the Tremulus Lune would be a candidate.

Re: Candle Flicker LEDs

Posted: Thu Jun 23, 2011 11:44 am
by modernage
Or perhaps this guy?

I'm extremely interested to see if this concept will work. :hello:

Re: Candle Flicker LEDs

Posted: Thu Jun 23, 2011 11:59 am
by multi_s
culturejam wrote:I've thought about this in the past. Not sure if they are suitable for audio use, as they may introduce noise from the integrated circuit that creates the flicker.


surely you could decouple the circuit with the led from the audio circuit if it was an issue. but also why not just make a random or an lfo that simulates candle flickering as its envelope and use just a regular led. maybe amplify shot noise or something like that. or if went with an mcu/lut the options for lfo wave are already basically unlimited.

Re: Candle Flicker LEDs

Posted: Thu Jun 23, 2011 12:28 pm
by hazelwould
Someone needs to do this with a PT2399, and get a nice random vibrato going. And add a filter (for the lofi).

Re: Candle Flicker LEDs

Posted: Thu Jun 23, 2011 1:28 pm
by multi_s
hazelwould wrote:Someone needs to do this with a PT2399, and get a nice random vibrato going. And add a filter (for the lofi).


ya thats more or less what the probability of a fax machine is only there is an S/H filter in between the noise gen and the variable resistor so its more like random steps instead of continuously random.

Re: Candle Flicker LEDs

Posted: Thu Jun 23, 2011 1:36 pm
by culturejam
multi_s wrote:surely you could decouple the circuit with the led from the audio circuit if it was an issue.

The only experience I had with this kind of thing was those flashing, strobing LEDs that Goldmine Electronics sells. They look cool as hell, as they morph through several colors as part of the pattern. But it put out a whine that I couldn't get rid of. But then again, that was a LONG time ago, and I know a lot more about electronics now than I did then.

multi_s wrote:but also why not just make a random or an lfo that simulates candle flickering as its envelope and use just a regular led.

Because it takes up more space than the LED that has it built in. I can't think of a way to do a real flicker effect without getting into microcontrollers. That is, I believe, how those LEDs do what they do. You could probably get close with a 555 and a few caps/resistors.

Actually, here's one that claims to be "seemingly random":
http://fnbcreations.net/Articles/FIREFLICKER.pdf

But that's a lot of parts.

Re: Candle Flicker LEDs

Posted: Thu Jun 23, 2011 1:57 pm
by multi_s
culturejam wrote:
multi_s wrote:surely you could decouple the circuit with the led from the audio circuit if it was an issue.

The only experience I had with this kind of thing was those flashing, strobing LEDs that Goldmine Electronics sells. They look cool as hell, as they morph through several colors as part of the pattern. But it put out a whine that I couldn't get rid of. But then again, that was a LONG time ago, and I know a lot more about electronics now than I did then.

multi_s wrote:but also why not just make a random or an lfo that simulates candle flickering as its envelope and use just a regular led.

Because it takes up more space than the LED that has it built in. I can't think of a way to do a real flicker effect without getting into microcontrollers. That is, I believe, how those LEDs do what they do. You could probably get close with a 555 and a few caps/resistors.

Actually, here's one that claims to be "seemingly random":
http://fnbcreations.net/Articles/FIREFLICKER.pdf

But that's a lot of parts.


maybe, but is it more space then building another whole circuit that can only do flicker? or having to have 2 led/ldrs? one for normal and one for flicker? maybe more equivalent in the grand scheme and probably more adjustable.

You can get random by simply observing a random process, ie noise. The campfire circuit in that document is neat but you can generate white noise a lot easier than that. A resistor/ diode and an op amp is enough. no mcu needed.

Anyways my point is not to poo poo on the idea but more to state you can already probably build the equivalent with (a very few) number of parts you already have in your drawer.

Re: Candle Flicker LEDs

Posted: Thu Jun 23, 2011 3:36 pm
by Bassus Sanguinis
dmcmahon wrote:So what can we do with these: http://evilmadscience.com/productsmenu/ ... 89-candled

Can we make a flickering tremolo?


...if it was any good in clipping, it might turn out an interesting feature in a noisy dirt pedal :)

Re: Candle Flicker LEDs

Posted: Thu Jun 23, 2011 4:26 pm
by eatyourguitar
the flicker led would be turning on and off very fast setup as clipping diode. if it does create noise or a whine or whatever than it would sound pretty cool since that noise would be modulated on/off/on/off. if the startup time is longer than half the wavelength than it wont do anything but clip like a normal led.

Re: Candle Flicker LEDs

Posted: Sun Jul 03, 2011 7:16 pm
by multi_s
dmcmahon asked to see so as a followup heres a quick demo i did today. usues an mcu and pwm to modulate the led with the famous rand() function from the c stdlib.

the plus of doing it this way and not with the candle led is that you can control the rate and depth. the mcu cost is on par with most s/h ics (LF398 etc) which woudl still require a timing setup (a 555 or something)

psuedocode is something like

endless loop{
if(time to change step){
pwm = rand() % depth}
}

http://www.youtube.com/watch?v=shg8Kt2w1Rg

Re: Candle Flicker LEDs

Posted: Sun Jul 03, 2011 7:34 pm
by Rygot
I'd like to see what people can do with this.

Re: Candle Flicker LEDs

Posted: Sun Jul 03, 2011 7:39 pm
by eatyourguitar
puttin in work on the breadboard with the camera handy. well done