Making bass wah to work in auto mode

[imperatormk]

Hey.

I found this bass wah schematic online ( http://members.shaw.ca/roma/wah-1b.gif ), but it has a switch that is supposed to simulate the actual pedal for activating the effect.

I was wondering if I can modify the schematic so it works in auto mode (no external trigger is needed). As I don't know much about this circuit, the best I can think of is feeding the input signal to the point where the foot switch is. That or using a 555 IC in astable mode. This of course might be utterly wrong.

Any suggestions appreciated!

[bluebunny]

I was wondering if I can modify the schematic so it works in auto mode (no external trigger is needed).

Do you mean like an auto-wah?  Or like an LFO-modulated filter?  Since the business end is being controlled by an LDR, I guess a whole pile of options could sit at the right-hand side of that schematic.

Welcome along, btw.   

[imperatormk]

Hey.

Do you mean like an auto-wah?  Or like an LFO-modulated filter?

What is the difference between the two? Which of them is simpler to construct?

Thanks!

[bluebunny]

The auto-wah kind opens (or closes) a filter according to your playing: strum or pick harder, the more the filter opens.  The LFO-modulated filter will just go open-close periodically.  Neither is "easier".  You could have, ahem, "fun" - whichever you choose.   

Have a go with the button.  Try stuff like "LFO", "auto wah", "lightwah", "pulsinator", ...