I cleaned the sensor light, but there was no change. However, it records 22 cal pellet velocities well, but not BBs and 177 cal pellets. It use to record 177 cal pellets, maybe 33% of the time, but BBs rarely in sunlight. Now, after 25 times, it has failed to record a 177 cal pellet velocity in the bright sunshine, some shade, and under a big fluorescent lamp (22 cal pellet worked). Not sure if LED lights will change that. Need a more sensitive chronograph, but those Prochrono are not cheap and are highly rated.