Posted on 5th September 2019 in the categories: Magnetics

Proximity Sensors and Magnets

Proximity Sensors

Without proximity sensors, cell phones wouldn’t be as user-friendly, the food and beverage industry wouldn’t operate under the same decontamination standards and manufacturing processes would be less efficient. The latest smart technologies also rely on accurate measurement, tracking, and monitoring; all of which proximity sensors provide.

How do proximity sensors work?

Proximity sensors emit an electromagnetic field or a beam of electromagnetic radiation and looks for changes in the field or return signal. The object being sensed is often referred to as the proximity sensor’s target. However, each target demands different sensors. For instance, a capacitive proximity sensor might be suitable for a plastic target while an inductive proximity sensor always requires a metal target.

Due to the absence of mechanical parts and lack of physical contact between the sensor and the sensed object, proximity sensors can have a high dependability and a long lifespan.

Types of proximity sensors

Differing from the more traditional option, proximity sensors don’t require a mechanical switch, level, or plunger to be pushed against a target. There are many types of proximity sensors, including:

  • Capacitive
  • Ultrasonic
  • Optical
  • Radar
  • Vision
  • Inductive

Inductive proximity sensors are the most commonly used, implemented in millions of processes worldwide to detect the presence or absence of metallic objects.

Magnetic proximity sensors

Magnetic proximity sensors, a non-contact device, are a type of inductive sensor. They operate through reed switch, inductive or variable reluctance, or hall effect operating principles. Essentially, they sense a magnetic target which in turn triggers the sensor when it enters detection range.

These sensors detect magnets through non-ferrous barriers such as:

  • Stainless steel
  • Aluminium
  • Plastic
  • Wood

This is done while withstanding shocks, vibration, dust, dirt, water, high temperatures, and other harsh industrial or environmental elements. Like all proximity sensors, there is no physical contact so magnetic sensors last significantly longer than traditional switches.

This type of inductive sensor is also used in the oil and gas industry, measuring variables on offshore rigs. This is mainly because they make the most durable option, since they can handle harsh conditions like saltwater, and are resistant to oil, grease, and dirt.

Smartphones and tablets

Commonly, proximity sensors are used in mobile devices. When the target is within range, the device lock screen will appear, emerging the device from sleep mode. Once awoken from sleep mode, if the proximity sensor’s target is still for an extended period the sensor will then ignore it. Therefore, the device will revert into sleep mode. For instance, during a phone call, proximity sensors detect accidental touchscreen taps when mobiles are held to the ear.

Other applications

  • Parking sensors
  • Aircraft landing gear
  • Ground proximity warning system for aviation safety
  • Vibration measurements of rotating shafts in machinery
  • Anti-aircraft warfare
  • Roller coasters

Goudsmit UK

High performance magnets from Goudsmit UK are used daily in hundreds of industrial applications worldwide. All magnetic products manufactured by Goudsmit UK also meet or exceed ISO 9001, AS 9120B and IATF 16949 quality standards.

Contact us today for more information at Or you can also speak to a member of our team call us on +44 (0) 2890 271 001.

For more information on our magnetic products visit our webpage or our products and services brochure here.

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