@crociquia, (or anyone else with input/advice!)
Let me just say how excited I was to come upon this thread! My current project has a lot in common with you and I read and re-read this thread, looking up all sources and materials. About me; I am a masters architecture student currently working on my thesis project in which I am collaborating with engineers. We are designinsg and building an environmentally responsive 'curtain' of sorts. This curtain is made up of many inflatable components. Each component has the potential to inflate or deflate thanks to a light sensor (each component has a light sensor and a fan attached to it )that triggers the arduino to tell the fan to blow in the positive when hit with light and reverse direction (suck air out) when sensing dark.
How did you project turn out? I see that the 'sensor' in your project is based on volume/sound input.
The sensor in my project is related to light. Right now I am struggling with figuring out exactly the right light sensor which will be attached to an inflatable component. (If anyone reading this has any light sensor suggestions that would be great! I have a list going but the important aspect is that these wont be directly attached to the arduino board. They have to exist inside these inflatable components. (see sketch attached) This light sensor will most likely have only 2 inputs and not work on a scale. IE it will trigger the arduino to tell the fan to turn in the positive direction when dark (filling the component with air) and turn the motor in reverse when the sensor senses light. (sucking out the air from the component)
I am dealing with the following issues. Many are the same as your past project.
1) hooking up multiple pc fans to 1 arduino board-
Did you resolve the power supply issue? Did you use an external 12 v DC power supply or did you follow @magicians suggestion of finding a relay board that can handle the large amount of voltage and channel it to the 5v arduino?
2) relay board- I realize that you needed a relay board to assign 5 fans to one relay as you had 6 columns of fans, and you needed the columns to act together as one. Is that correct? Since my fans are all acting independent of one another, ie responding to their individual light sensors, Do I need a relay fan ? I know I need something that will handle the overload of voltage going to the 5v arduino board.
3) physically handling the wiring from that many fans-
I am assuming you had an interesting layout and we are talking about long chords all ending at one point/the arduino board. How did the wiring turn out?
4) Reversing motor direction of fans-
I have found a helfpul link here about reversing motors http://itp.nyu.edu/physcomp/Labs/DCMotorControl
but if anyone has any specific tips about my project wow that would be much appreciated!
5)Finally, @crociqua if you are open to sharing your code that would be incredibly appreciated. Pictures or a link to your project would be great too! love those arduino + fan projects! Ha
ps see the attached PDF for hopefully a more helpful explanation of project goals/issues!