Build A Digital Tachometer/RPM Counter

Data & Observations
           The best part of any project or tutorial is watching it work just as planned. The video below uses a computer fan to test the digital tachometer and make sure that it works as an rpm counter.

           The battery running the fan was not at 100% so the fan wasn't able to reach its maximum speed of 3200 rpm, however it did have no problem reaching the minimum of 1200 rpm, notice it would go to 1240~~1250 but never exactly 1200....maybe the manufacturer is cheating me! Either way, the digital tachometer is working perfectly as an rpm counter and if I ever need to add it to an application all the info needed is here.