Discussion in 'The Projects Forum' started by iceman, Jul 29, 2008.
Please help me about this IC... I need a circuit to control different lights controlled by a music.
What kind of help are you looking for?
Here is the datasheet. I found it using our electronic resouces forum.
The attached circuit is the circuit that I made and am using with my stereo player. Apply the music to where is mentioned 'signal in'. The diode can be any ordinary diode and is shown in order to prevent wrong polarity. The 470 ohm resistor is a current limiting resistor. It would be better if you used 1/2 watt resistor here if supply voltage is greater than 6v. When music is applied, the LEDs will light on and off very quickly as if they were dancing. When pin 9 of the LM3915 is connected to pin 3, the LEDs dance in a dot mode, otherwise in bar mode. The switch is there to control this.
Pins 1 and 10-18 are the output pins of the LM3915. If the input voltage is less than 6v, the 470 ohm resistor can be omitted.
Dot mode means that 1 LED will be on once, then off and another will be on. Bar mode means that it will dance like an equalizer. A few on at the same time.
The LM3915 works a lot better with music if it is fed from the output of one of the peak detector circuits shown in the datasheet.
Your vision cannot follow the quick fluctuations of the half-wave display so the peak detector holds the peak level for about half a second.