Using electret mic as input for tip31 for sound reactive leds?

[sunny1992]

Audio guru i am using your provided scematic to run led strip that works on 12v 1a powersupply. But it didnt worked, please suggest the changes that i need to make.

The Instructable that used only a TIP31 power transistor as an LED driver circuit has many problems because it was designed by as 10 years old kid who knows nothing about electronics. It blows up the amplifier, LEDs and TIP31 transistor because it is missing resistors to limit current.

The LM386 can drive an 8 ohm speaker with peak current of 400mA so it is perfect as an LED driver circuit.
Its output pin is normally at half the supply voltage which will light red and yellow LEDs all the time. If a resistor powers a diode at 0.7V then a pot can apply the variable voltage to the inverting input pin of the LM386 to reduce the idle voltage until the LEDs do not light. Then sounds will light the LEDs.
The LM386 acts like a half-wave rectifier so the LEDs are lighted for half the time and their peak current is 40mA but their average current is 20mA.
Try it (I didn't).

 

[audioguru]

The datasheet for the LM386 shows that with a 12V supply it gets extremely hot and its output goes only as high as about 6.5V that will probably not light a 12V LED strip. That is why I used 9V and separate LEDs.

 

[sunny1992]

Thank you for the reply. Please guide then what do you suggest? Instead of lm386 which amp should i use and what modification do i have to make...

The datasheet for the LM386 shows that with a 12V supply it gets extremely hot and its output goes only as high as about 6.5V that will probably not light a 12V LED strip. That is why I used 9V and separate LEDs.

 

[audioguru]

Find an amplifier that has an output that goes up to 12VDC. An LM1875 is still made and is available. Use it with a 30V supply. Change R4 in its datasheet to 200k. Its heatsink size depends on the power needed by the LED strip.