Fuzzy Dicer sweep filter?

[exoshell]

Hi,

I recently built the Fuzzy Dicer circuit from Handmade Electronic Music by Nicolas Collins. It uses multiple 4049 stages to generate distortion and the output is then fed into one input of a 4093. The other input is connected to the output with a photo resistor. This loop then connected to ground through a 0.1 uF capacitor. I've built this circuit into a wah pedal case and use a potentiometer to  vary the intensity of an LED placed over the photo resistor which filter the sound.

I would like to add the ability flash the LED over the photo resistor when I strike a note on the guitar. I would like to LED to light up and then slowly discharge. I want it to only triggered once and repeatedly flash the LED.  How would I go about this and how complex is it?

BTW The schematic is viewable via Google books preview on page 198.

Thanks

[mr.adambeck]

I believe in his book he covers how to get a signal to light an LED (I know it's at least in the gate/ducking schematic, may also be separate, but haven't looked at that book for a little while.), and then use a photo resistor to convert it to resistance.  You would just replace one of the pots with that resistor.