This little sensor is a no contact switch (a fork shaped photointerrupter). It detects the presence of a small object passing between the two arms of the fork.

Capteur

In a program that manages real-time events, this sensor lets one trigger sound and visual effects. It connects to a sensor interface like the « 4 analog inputs » card.

Basic principle, for example with a rotating object

Caracteristics

This sensor detects the passage of an opaque object through its fork. These objects must be small enough to go through the fork arms without touching them (which could damage the sensor). It can work for a large object that has a thin extension.
However, it is not adapted to slow movements, that are better detected with a Light trigger sensor, a little harder to integrate into a mecanism.

Exemple

This sensor can detect metallic markings placed at specific places on a film roll. It can find the localization of a toothed wheel in a mecanism, or a belt, if equipped with the right pattern. It lets one control a mecanism over time by detecting position markings.

Sensor data display

A short demonstration video (created by Lysandre Fournié) presents the data from an optical fork sensor and of the light trigger.