Electro-optical sensors, optical detectors or fiber optic sensors detect real images or light and convert them to signals conveyed on fiber optic cable. Optical detection is far from limited, serving in laboratories, factories and businesses. There are even automotive optical sensors, such as those that detect steering wheel rotation.

Besides appearing in a range of places, however, optical sensor applications, themselves, are diverse.

Optical sensors are vital to many scanners, tachometers and other devices and each of the following sensor categories has optical versions:

1. Displacement optical sensors measure or control the variable distance between two objects, for example, to control machine movements.

2. Dissolved oxygen optical detectors detect DO levels in liquids, especially water for biological and environmental testing.

3. Gas sensors detect gas concentrations, for both industrial and safety applications.

4. Color optical sensors detect target colors or ranges for quality control and laboratory tests.

5. Fluid sensors read out fluid levels in containers or signal an alert at minimum or maximum levels.

Action Steps
The best contacts and resources to help you get it done

Track displacement with optical detection

Optical displacement sensors serve measurement jobs well. Optical measurements are often practical and quick, sometimes comparable to measurement by laser sensor.

I recommend: Micro-Epsilon carries a triangulating laser, as well as optical displacement sensors. They also carry many other types of measuring and positioning devices, including the charge coupled device (CCD) sensor. Philtec distributes optical displacement sensors for distance, displacement and vibration measurement and its website contains quite a bit of optical sensors information.

Locate optical sensors that measure dissolved oxygen

Sometimes divers and biologists prefer the newer optical technology that requires relatively less care than electrode-based DO sensors. For instance, some conventional sensors have more variables because of changes in the electrolyte fluid during heavy use. Also, optical sensors often work better in stagnant water.

I recommend: AADI specializes in oceanic science and has many quality sensors, including the optical dissolved oxygen sensor. Another source is Global Water Instrumentation, Inc. which carries a model that features long life and bio-fouling resistance. Their unit is unaffected by water current or a lack thereof.

Experiment with optical sensors to monitor packaging or sort batches

Optical color sensors are excellent for sorting batches, like bricks; and keeping consistency between batches, like beverages. They also help perform quality control of your packaging.

I recommend: Pepperl+Fuchs, Inc. carries many types of photoelectric sensors, including optical color and contrast sorting sensors. Avago Technologies is another source for an optical fiber sensor for color. They have a number of red, green, blue (RGB) products, including four-channel color sensors suitable for quality control applications.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  In combination with a reflector, an optical sensor functions as a proximity sensor.