Set at 5900 RPM, my 10 inch table saw attracts notice when I turn it on and a few take steps backward. Small boards go through like a meat slicer. I did pulley calculations for this setting. I wondered if this would work for electric measurement of RPM? At high RPM, it seems hole in blade would be safest way to go.
Left side is lamp that shines through hole in blade to photo-transistor circuit on right with suitable resistor to connect frequency counter on two outputs.
Any ideas others are using?
