LM3915 / LM3916 VU Meter
National Semiconductor » LM3914, LM3915, LM3916
The LED VU Meter was the height of late 80-s boombox technology. This instructable will build one out on the breadboard. Who doesn't like blinking lights...
Wire the LM3916 Circuit
I skipped two things, I did not use the capacitor as it is only necessary if you have more than 6" of cable between the LEDs and the chip, and I also did not use the 7.5 k resistor in the diagram going to pin 6/7. your mileage may vary.
3Pass through for sound
So I wired up two 1/8" stereo jacks wire the two together, and then hang 3 wires off of one, the negative will go to pin 4 on both chips, while the left signal will go to pin 5 on one chip, and pin5 on the other chip.
WIre the LEDs
Then pin 1 should go to the first pin on the LED, followed by pins 18-10 so they will light up in order.
As you can see in the second pic, I got a little sloppier on the second set of LEDs and just used wires from a jumper kit so its a little messy.
Now you can live large like Radio Raheem, this would fit nicely in the ipod nano box wouldn't it...
Except you can't fit 20D batteries in a nano box...
PCB Pricing: https://jlcpcb.com/quote