LED VU meter that dances to computer music

Step 3 Turn on some songs and sit back and watch

The final circuit is shown here.

This is a note from where I got the circuit drawing: "I like to see lights move to music. This project will indicate the volume level of the audio going to your speakers by lighting up LEDS. The LEDS can be any color so mix them up and really make it look good. The input of the circuit is connected to the speaker output of your audio amplifier. You want to build two identical units to indicate both right and left channels. The input signal level is adjusted by the 10k ohm VR. If you wish to make a very large scale model of this unit and hang it on your wall there is an optional output transistor that can drive many LEDS at once. The unit I built drove three LEDS for each output. The sequence of the LEDS lighting are as follows Pin 1, 18, 17, 16, 15, 14, 13, 12, 11, 10."

I only did this for 1 channel but plan add improvements.

Take a look at the video for results.

Some things I need to fix are:
All of the 10 LED's do not light up. I need to make an amplifier of some sort but dont have too much expierence in this.
Make this work with a microphone element
Add function for two channels
Add multiple LED's in place of each 1 LED (maybe 3x10 = 30LED)
Also figure out how to connect the microphone element as I have no idea what the picture below shows

Comments

[andrewj41]

Try adding a 4u7 capacitor going from the positive rail to pin 7 of the LM3915 in this project? It should give some rather pleasing results especially in LED intensity for this project! It will hopefully sort out the fact that only 3 LEDs are lighting! Let me know how you get on.

[mzupin]

much better!!!!! but still not perfect.

[truck56]

Hello,,I have built this unit a couple ways now. First,,if you use the actual speaker output from your sterio amp instead of the sound card on your pc,,all of the leds light up no problem!! I have also used a transistor on the out put pins of the chip instead of connecting them to the leds and can drive 11 leds off the transistor!! Its totals 110 leds and when connected to my sterio amp speaker output they all light up as the volume is increased. Only thing I would like to do is add an amp to the circuit board with a mic so it dosent have to be connected to a speaker at all,,just the sounds in the room should light it up !! Im NEW at this and dont really no a whole lot about electronics but if you would like any info on what i have just posted,,e-mail me at  [e-mail]          and i will try to help asap ! I also have a video but dont no how to put it here ??

[Werewolve]

Why did only the first 3 Led's light up?

[elvedin]

each that LED, lights up on different frequency. first 3 LED's are probably for lower frequency's like 30 to 160 Hz other LED's are for higher frequency's 200 Hz to 16Khz. If there is a signal from 30 to 160 Hz than that 3 LED's will light up and if there is a signal from 200 Hz to 16Khz other 7 LED's will also light up so the other 7 LED's didn't light up because there wasn't higher frequency's to light them up. sorry for the bad English I'm not good at it

[likeastone9999]

i think the reason they all didnt light up i believe is because the resistor value is a little high for led's i'd try a 330ohm. colors are orange orange brown gold... i used those for my led's in my speakers and with them, the leds haven't burnt out or gotten over powered even on 100% power from my 105x7 watt receiver.. nice job!!!!! im gonna try to get one built by next week and install it in my computer case

[Demircat]

For the optional output for multiple LEDs, does the input (point after the resistor) lead into pin 5, or somewhere else? With that, is there a recommended limit as to how many LEDs to use? Thank you!