I am interested in building a nice freq/amplitude visualizer with Arduino. Originally, I had hope to do the band pass filtering all in software. Doesn't look like anyone has done that yet and not sure if it is possible. In order to try to avoid using a load of discreet components I started looking for an IC. I looked at the white papers for a BA3834 . A webpage claimed it is able to do 7 band pass filters in and serial out which sounds usable but I only see a b and c and assume those are inputs? I am new to the hobby and really not good at reading some of these chip layouts yet. Can anyone tell me if this is a good chip for this purpose and if not perhaps make a recommendation? I just want to get something up and running first and make it fancy after I figure out the code. I would not mind if the lower frequency lights lit up when a higher freq came through as long as all the lights below the "correct" one came on. I think that effect would be OK. This would only require high pass filters yes? Would it be easier to find an IC like that? Any help will be appreciated.
I had hope to do the band pass filtering all in software. Doesn't look like anyone has done that yet and not sure if it is possible.
When you want multiple frequency bands, that's normally done with FFT
(http://en.wikipedia.org/wiki/Fast_Fourier_transform). There is an FFT library for the Arduino so you don't have to write the code from scratch. I'm sure there are some limitations since the Arduino isn't a particularly fast processor, but I don't know what those limitations are.... You can find Arduino spectrum analyzers that use FFT..
I looked at the white papers for a BA3834 . A webpage claimed it is able to do 7 band pass filters in and serial out which sounds usable but I only see a b and c and assume those are inputs?
I'm not familiar with that one, but it might be similar to the MSGEQ7
(http://www.mix-sig.com/datasheets/MSGEQ7.pdf), which you can buy from SparkFun. I've never used it, but the MSGEQ7 is a slick little chip. It has one time-multiplexed output, so you can get 7 channels/bands into one Arduino ADC input. Plus of course, it has the frequency-filtering, and it converts the AC waveform to a DC output that's easily handled by the Arduino.
Looks like I have some reading to do. Thank you.
OK thanks to your info about this chip name, I found this.
Looks like a great place to start chopping :)
I have no intention of using any fonts or dmd's so Much of it can go bye bye I think.
I plan to use some regular LED's and somewhere I saw a chip that lets serial out drive a ton of them with a separate power source by switching there ground on and off. I plan to mount them into some plexi for edge lighting. I think I need to study arrays a tad more though. Trying to look at the left(band) right (band) is hurting my head. I understand what it does but I can't visualize it yet. Thanks for the help.
I built a bi-color LED Matrix stereo Audio Spectrum Visualizer using MSGEQ7 ICs with info gathered also from http://tronixstuff.com/2013/01/31/tutorial-arduino-and-the-msgeq7-spectrum-analyzer/ (http://tronixstuff.com/2013/01/31/tutorial-arduino-and-the-msgeq7-spectrum-analyzer/).
If you are interested, you may visit http://www.instructables.com/id/Arduino-based-Bi-color-LED-Matrix-Audio-Spectrum-V/ (http://www.instructables.com/id/Arduino-based-Bi-color-LED-Matrix-Audio-Spectrum-V/) for detail.
Hope to see your completed project in action.