Proximity sensors are designed to detect the presence and proximity of an object in range without any physical contact, using sound, light, infrared or electromagnetic fields instead.
Types of Proximity Sensor
- Inductive - An inductive sensor provides non-contact detection of metallic objects. Some sensors can target both ferrous and non-ferrous metals, while others specialise in sensing only one type.
- Ultrasonic - Ultrasonic sensors work by emitting a short burst of ultrasonic sound at a specific frequency towards the target. When the target reflects the sound back to the sensor, the sensor measures the time it takes for the echo to return. The sensor will use the time it takes the soundwave to travel back to calculate the distance between the sensor and the object.
- Capacitive - Capacitive sensors can detect metallic and non-metallic materials. They can detect and measure materials that are conductive or have a greater dielectric constant than air using an electrical field.
- Infrared - Infrared sensors measure light with a wavelength in the IR spectrum (>700nm). They are not good at detecting visible light. IR sensors can recognise light from either external or built-in light sources.
