[Gdeaver]

Using a DC brushed motor for a tachometer in 2012 to control shooter RPM was a result of our programming team refusing to deal with the issue digitally. We had a hall effect solution as non-contact 2 pulse per revolution and a 16 pulse per revolution solution. Interestingly when an analog solution was provided the code happened. Originally a small motor was chosen that would give a 0 to 9 volt solution in the range of rpm's our shooter would be operating taking advantage of the wider range of the c-rio ADC. We asked the GDC about the legality of using a DC motor as a tachometer that was not on the approved motor list. In was a sensor in our view. The GDC nixed our use of the motor and we turned to a KOP motor for legality. We chose the throttle motor. A filter turns the pulsed voltage of the motor (generator) into a smooth voltage proportional to rotational velocity. It worked very well. Also was an excuse to bring in a scope and show the student a little about filtering. We are currently working on eliminating our programming team's fear of digital encoders (Quadrature). RPM's where measured by analog solutions for years before the digital solution was economically possible.