However, Pioneer 4 did not come close enough to trigger its photoelectric sensor.

A photoelectric sensor protruded from the center of the ring.

The distance was not close enough to trigger the photoelectric sensor.

The light and rotation are activated automatically by a photoelectric sensor.

But clear labels cannot be detected by photoelectric sensors.

The streetlights were clicking off as their photoelectric sensors told them the sun was coming up.

They include automatic passenger counters which are located above the doorways, using photoelectric sensors.

A self-contained photoelectric sensor contains the optics, along with the electronics.

Because of technological progress, self-contained photoelectric sensors have become increasingly smaller.

The women rushed out screaming, just as photoelectric sensors triggered a smoke alarm.