controlling lm3914's with an arduino's output.

i want to create a spectrum analyzer for audio from a microphone (not audio line from music player)

i came across lm3914’s and from what i read theyre pretty common. i was curious if there is a way to control them directly from the arduino. all the examples ive come across use pot’s. however i did find a post that suggested using a opamp and the arduino’s analog out for something similar…
is this what im going to want to do?

i want to end up with 5 lm3914’s controlling 10 leds each. then the audio from the mic will be split into 5 bands, analyzed, and used to adjust the lm3914’s accordingly.

am i headed in the right direction or is this even possible?
im quite lacking in experience (if you cant tell) but i am willing to learn.


What you describe is POSSIBLE, given some additional electronics on each analagWrite pin to convert the PWM to a real variable voltage (the PWM outputs are ON for a percentage of the time and OFF for the rest, giving an "average voltage" that is analog, but the 3914 wants an steady voltage level...)

But it would be easier to control the LEDs with the arduino digitially using other chips. (Potentially, you don't need any other chips at all, but that might not be the way to go if you're trying to run a continuous real-time FFT algorithm!)

what "other chips" would i be able to use to control them digitally? i really wasn't too set in stone with any plans so any ideas would be great.

an FFT algorithm is what i would use to analyze the audio right?

Well, for example there is the TI TLC5940, which will drive 16 LEDs with no need for resistors/etc. Simpler shift registers would work as well.