Adding An On/off Switch To A Circuit

[hooglebug]

i got a velleman sound to light kit to see if i could stick it in a guitar to light up as you play. it will work, but theres only a sensitivity pot to turn it off with, and i thought an on/off switch would be a useful addition. does anyone know how id go about adding one?

heres the schematic if that helps - link

[Prostheta]

Replace it with a 220k pull pot or the switch/pot's switch break the earth connection to the circuit from the battery. This might introduce spikes into the audio lines of the instrument however, so it might be worth putting an electrolytic capacitor over the power lines of the order 1uF - 10uF? This will smooth the power transitions between on and off slightly.

[hooglebug]

ah ok thanks for that.

did it and it worked. shall have to wait for when/if i ever put it in a guitar to see if it causes any problems

[hooglebug]

ok back to this again. i took out the microphone and wired in the output of the guitar to the + and - so that it works off the pickups themselves rather than a microphone.

it works, but theres a pop when turning it on, pops when switching between pickups, and noise when i turn the volume knob. nothing with the tone though. would putting the electrolytic cap in sort this out? and so i know, that goes in over the battery? so the + and - of the cap go in on the + and - of the battery?

also, how would i add more leds to it? would i need to add more resistors?