10. Frekans değerine göre LED leri yakma

Assembly is broken into 4 parts:

• The audio input — the circuitry that takes the signal from the audio jack.
• High frequency — blinks the blue LEDs when high-frequency tones play.
• Mid frequency — blinks the green LEDs when mid-frequency tones play.
• Low frequency — blinks the red LEDs when low-frequency tones play.

http://makezine.com/projects/easy-led-color-organ/