Sorry, sir zoomkat, but how can you use paddle switches in fan status detection? Could you give us a drawing? I kept on imagining putting the switch inside the fan and blades getting stuck in the switch.
I would like to try sir goodhen's suggestion but I just want to clarify this... is the code the same for using the blade as interrupt (like this)and using a reflective material (like this)?
Could I use the code here http://www.pyroelectro.com/tutorials/tachometer_rpm_arduino/software.html for the IR reflective sensor? I want to measure RPM like this (http://www.stumbleupon.com/su/9XvNYO/embedded-lab.com/blog?p=2425) but the site used a different controller. Also, could you suggest an IR module from sparkfun that I could use for this project?
light is intense enough to register as logic level. I doubt using the adc is an option-it's too slow for this purpose. Using an opamp (or a transistor) would be pretty simple if the light levels are too low.
Could I use the code here http://www.pyroelectro.com/tutorials/tachometer_rpm_arduino/software.html for the IR reflective sensor?