Spindle RPM counter
Programmable universal counter made out of a kit (the housing is home made)
Overallview of the stroboscope on the spindle pulley of the drill/mill
Home made stroboscope on the PC and glued on the lower pulley rim.
There are 120 strokes which the cell interface divides by 2 and then the counter counts for one second showing the RPM of the spindle.