{"id":9284,"date":"2022-12-16T09:52:35","date_gmt":"2022-12-16T01:52:35","guid":{"rendered":"https:\/\/store.west-hn.com\/?p=9284"},"modified":"2022-12-12T04:47:06","modified_gmt":"2022-12-11T20:47:06","slug":"iot-sensor-presence-of-proximity","status":"publish","type":"post","link":"https:\/\/store.west-hn.com\/en\/iot-sensor-presence-of-proximity\/","title":{"rendered":"IoT Sensors - Presence Proximity Sensors"},"content":{"rendered":"

summarize<\/h2>

A proximity sensor is a type of sensor that can detect the presence of nearby objects without any physical contact with thetransducers<\/a>. Proximity sensors typically emit electromagnetic fields or beams of electromagnetic radiation (e.g., infrared) and look for changes in the electromagnetic fields or return signals. The object being sensed is often referred to as the proximity sensor target. Different proximity sensor targets require different sensors. For example, capacitive proximity sensors or photoelectric sensors may be suitable for plastic targets; inductive proximity sensors always require metal targets.<\/p>

Because there are no mechanical parts, there is a lack of physical contact between the sensor and the sensed object. Proximity sensors can be highly reliable and have a long functional life. Proximity sensors are also used in machine vibration monitoring to measure changes in the distance between a shaft and its support bearing. This is common in large steam turbines, compressors and motors that use sleeve bearings. Proximity sensors adjusted to very short distances are often used as touch switches.<\/p>

Common Application Areas<\/h2>
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Parking sensors, systems mounted on the bumper of a car or on the side of a car that sense the distance to a nearby car for parking, these systems use electromagnetic or ultrasonic sensors<\/p><\/div>\n\n

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Aviation Safety Ground Proximity Warning System (GPWS), which displays a graph of two aircraft paths, the lower of which triggers the GPWS (ground proximity warning system)<\/p><\/div>\n\n

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Piston engine determines stopping position<\/figcaption><\/figure><\/div><\/div>
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An automatic faucet that opens its valve to allow water to flow in response to the presence of the user's hand in the vicinity. After a few seconds or when the presence of the user's hand is no longer detected, the faucet closes its valve again<\/p><\/div>\n\n

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Beverage and food can production lines: During the operation of the line, at a certain point it is necessary to stop or perform other operations that require sensors to sense the position of arrival.<\/p><\/div>\n\n

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Roller coasters: with sharp turns, steepslanted<\/a>Position monitoring during the process of<\/figcaption><\/figure><\/div><\/div>
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Air defense warfare: Initially, sensors were optical and acoustic devices developed during World War I and continued into the 1930s, but were soon replaced by radar, which in turn was supplemented by optoelectronic technology in the 1980s<\/p><\/div>\n\n

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Conveyor System: A common type of mechanical handling device that moves materials from one location to another. Conveyors are particularly useful in applications involving the transportation of heavy or bulky materials<\/p><\/div>\n\n

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Touchscreen: Users can input or control information processing systems through simple or multi-touch gestures by touching the screen with a special stylus or one or more fingers.<\/p><\/div><\/div>

Sensor Classification<\/h2>

Capacitive Sensors<\/h3>\n\n

Capacitive sensors are a technology based on capacitive coupling that can detect and measure any dielectric that is electrically conductive or has a dielectric different from air. Many types of sensors use capacitive sensing, including sensors for detecting and measuring proximity, pressure, position and displacement, force, humidity, liquid level, and acceleration. Capacitive sensing-based human-machine interface devices, such as touchpads, can replace computer mice. Digital audio players, cell phones, and tablet computers sometimes use capacitive-sensing touchscreens as input devices. Capacitive sensors can also replace mechanical buttons.<\/p><\/div>\n\n

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OMRON Capacitive Sensor E2K-X15MF1<\/figcaption><\/figure><\/div><\/div>

Doppler effect sensor<\/h3>\n\n

The Doppler effect is defined as the apparent difference between the frequency at which a sound or light wave leaves a light source and the frequency at which it reaches an observer, caused by the relative motion of the observer and the source. When a listener moves toward a stationary source, the pitch (frequency) of the sound heard is higher than when the listener is stationary. If the listener moves away from the stationary source, a lower pitch is heard.<\/p><\/div>\n\n

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Geometry of the Doppler effect in radar applications<\/figcaption><\/figure><\/div><\/div>

Inductive Sensors<\/h3>\n\n

A device that utilizes the principle of electromagnetic induction to detect or measure objects. When current flows through an inductor, the inductor generates a magnetic field; or, when the magnetic field through the inductor changes, current will flow through the circuit containing the inductor. This effect can be used to detect metallic objects that interact with the magnetic field. Non-metallic substances such as liquids or certain dirt do not interact with magnetic fields, so inductive sensors can operate in wet or dirty conditions.<\/p><\/div>\n\n

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Keltronik's Iron Inductive Proximity Sensor<\/figcaption><\/figure><\/div><\/div>

Magnetic Sensors<\/h3>\n\n

Magnetic sensors use GMR (giant magnetoresistive effect) technology. The measuring cell consists of a resistor with several very fine ferromagnetic and non-magnetic layers. Two of the GMR resistors are used to form a conventional Wheatstone bridge circuit, which produces a large signal proportional to the magnetic field when a magnetic field is present. A threshold is defined and the output signal is switched by a comparator.<\/p>\n\n