555 timer and lm324 circuit for sight and sound

Hello all,

I need some help with my detector circuit. I am trying to obtain seperate pulse sounds as my 3 LED's light up. I am using a voltage divider circuit and as voltage decreases my lm324 will output to a low for one LED to come on (which is tied to 9Volts). As the voltage being sensed by other lm324's (+) pin continues to decrease, their output produces their LED's to turn on.

NOW here is my question. How can I use my 555 timer to produce different tones or pulse lengths for each LED being turned on? I only want to use one speaker in the circuit.

Post a circuit.

schematic for divider circuit and 555 timer

This is the schematic I made. I have been attempting to run a wire from the trigger pin 2 of the 555, but that is very unsuccessful. I am varying my voltage across the +'s of my lm324 to see that the LED's work. I am just unsure how to incorporate the 555 timer. If any one knows a better method, I am open to all suggestions. Thanks for your time.