Does anyone know how to create a very slow auto volume swell

[moid]

Hi everyone

I'm looking for a way to allow an effect to really slowly fade in and out over a dry input signal without a footcontrol like an expression pedal - for example I'd like a fuzz effect to very slowly fade in over the dry signal and eventually completely replace it and then fade away again to reveal the dry signal... and repeat, but in cycles that last 10 - 30 seconds or more. I'm guessing this is some sort of LFO, but I haven't been able to find a vero board layout that contains an LFO that is that slow, so perhaps LFOs don't do this and I need a different control that I don't know the name of? I just want to have the volume of the effect slowly rise and fall very gradually - so some sort of auto swell where I have a pot that controls the length of time the swell takes and another pot to set the volume of the swell (this is the one that needs to be automated like an LFO). I'm not looking for an envelope control where input volume triggers an event; I want this fade in / out effect to run all the time (like an ultra slow phaser or flanger) If anyone has any ideas about how I could look into this I'd be really grateful. Thanks for reading.

[lordgalvar]

Well the moogfooger phaser's LFO goes up to a 90 second sweep, so a 45 second "rise". Copilot has made some super slow LFOs (even slower than the moog) that were one off/custom.

I think it might be fun/easy to use and arduino and use that and program an LFO. If the fuzz has CV in, the thing already runs at 5v. If it has exp in, have the arduino drive and LED/LDR/vactrol kinda setup.

I'm sure Autopilot would make you a broadcast that goes slow if you ask and don't want to do all the work/investment.

The other options are using something like a PLL chip (maybe?), 555 timer, or an op-amp LFO circuit and just bend it until you get where you want. Try changing the resistor and cap values around the rate control on a typical 555 timer.

Something I just thought of is using/repurposing an old function generator. Just make some kind of adapter/LDR setup for that. Those can make LFOs of all shapes and times. Here is one built for arduino https://www.sparkfun.com/products/11420 but, more importantly, it has datasheets for the chips that are used to make the signals. Don't know how slow it goes though (says resolution is 0.02hz which is 50 seconds)...but it might help lead you on your way.

Here is one that goes to 0.01hz http://www.ebay.com/itm/291250697392

I dunno if any of this helps. The Arduino seems like an easy, quick way to do this though

[moid]

Thanks very much lordgalvar. I didn't know that the Moogerfooger could go so slow - it sounds great, but somewhat too expensive for my budget alas. I'm fairly new to pedal building so it looks like my request is way beyond my skills if it requires arduino alas - I can't program Asking someone else to do this is also too expensive. I was really hoping that there might be a vero layout for a pedal with a similar function that I could adapt, but it's obviously not going to be that easy.

What you are saying about a 555 timer - presumably the resistor and cap values would be the ones that affect the power or signal (I'm not sure which) going into the 555? Would the output from that go to a potentiometer of some kind? If so would the fuzz signal go to lug 3, the 555 go to lug 1 and lug 2 would go to the output ? If this is possible maybe I could look for a vero layout with a 555 in it that is used as some sort of sweep and then play with the components around it. Maybe a phaser or tremolo would be good to look at?

Thank you very much for your suggestions though, I will look for more info about 555 chips and see if I can find something.

[lordgalvar]

There are a ton of 555 circuits out there, but I suggest just running pin three (or your triangle waveform out...) to drive an LED. Then use an LDR to change the resistance on the part of the fuzz where a pot would go (either fuzz or volume or something). Just look for 555 LFO or something. I'm sorry that I don't really know anything about vero layouts.

[moid]

Thanks very much, you've given me some good places to start and I had no idea beforehand I'll start researching as soon as I get paid at the end of the month; it's time to buy some 555s!