VU meter robot face


Upon starting my Arduino adventures/misfortunes one of my first projects was hooking a resistor and an LED to the board and making it blink. But just like those famous potato chips (Or crisps or thins or tater friedos) who can eat just one! One of the coolest things about LEDs and microcontrollers is the ability to combine them and make those groovy glowing diodes blink, fade or dance around in response to an input. Well, maybe not LITERALLY dancing, but..

 Anyway, this is just a simple LED project that I completely ripped off from this:

 I can't claim any credit but my thanks go out to the person who put the blog together! It's really well written and the code is dead simple to tune and works well. The only changes I made were altering the wiring order so the eyes lit up at a low level and the "sweep" went from center out. It works fine off a regular line signal and plays well with a little lm386 amp I've been fooling with. Google  "lm386" and it'll turn up a heap of nifty and cheap amplification projects.

About the only downside to this scheme is the fact that it uses quite a few pins. I did double up the eyes and the center mouth LED's which whittled the count down to 10 pins running 12 LED's but it's still a lot. I may fool with it some and combine my Charlieplexing experiments and reduce the number of required pins even further. Or maybe someone else will figure it out so I don't have to!

Here's the charlieplexing stuff I worked through a while back :

I actually made a PCB that used an ATINY 85 and was making good progress. Seems like the code on the instructable regarding the pin assignments was wonky or something. But I finally got it working using the hardware described. I may revisit it and see if I could get something similar working with robot face!

Some bored soul may want to look at it as well!

The 2nd vid is with your code bdk6. I also doubled up the LEDs and got it down to 5 pins. Could be 4 with this setup if the eyes weren't controlled by the meter.

Thanks for the input guys!

Thanks for the input guys! I’ll try the code bdk and post a video.

I have some of these bajdi : but I haven’t done anything with them :frowning:

One of the things I wanted was something simple that didn’t require any extra hardware but it would be cool to get the pin count down.

I did some charlieplexing stuff and ran 12 LED’s off 4 pins so that would be super to combine the VU meter stuff with that. The charlieplex test board I was working with actually dropped the resistor count so that would be nice as well.

I’ll add some of that stuff to this post so some of you smart folks can think on it :smiley:


I posted a vid using your

I posted a vid using your code bdk6. It seems to work fine but there were a couple of little typos in the code.