I have to paddlewheel setup on the stern and plugged into the arduino UNO. I’m getting consistent analog readings of; 20-30 for OFF and 700-900 for ON. The digital cutoff point is around 400. If I take it outside ambient UV light will cause the OFF readings to jump up to 200-300 so I’ll need to build a cowling to go over the whole apparatus to block out ambient light. I used the RPM photogate code available here to test the sensor’s digital readings.