Sensors have several sensing methods, principles and differences

The sensor has several sensing methods, principles and differences. As the name suggests, the sensor triggers work by detecting a certain medium. For example, human body sensing is the detection of human motion, respiration, temperature, etc. Do you know how the sensor works? let us see.

1. Proximity (proximity) sensing

Proximity sensing can be classified as contact or non-contact, analog or digital. The choice of sensor depends on physical, environmental and control conditions. These include:

Mechanical: Any suitable mechanical/electrical switch can be used, but since a certain amount of force is required to operate a mechanical switch, a microswitch is usually used.

Pneumatic: These proximity sensors work by interfering with airflow.

Optical: Optical proximity sensors fall on light-sensitive devices such as photocells by breaking the beam. However, during arc welding, the optical sensor may be covered with flash, and airborne dust and smoke may obstruct light transmission.

Electrical: Electrical proximity sensors can be contact or non-contact. Simple touch sensors allow the sensor and element to form a complete circuit. Non-contact electronic proximity sensors rely on sensing principles to detect metals or capacitors.

Range Sensing: Range sensing involves detecting the distance between the part and the distance detection location, although they can also be used as proximity sensors. The distance sensor uses non-contact analog technology. Short distances from a few millimeters to hundreds of millimeters can be sensed by capacitive, inductive and magnetic techniques. The various energy waves emitted, such as radio waves, sound waves, and lasers, are used to sense longer distances.

2. Force induction

There are six forces that can be induced. In each case, the application of force can be static (static) or dynamic. Force is a vector because it must be specified in magnitude and direction. Therefore, a force sensor is an analog operation that is sensitive to the direction of its motion. The six forces are: tension, compression, shear, torsion, bending, and friction.

Perception techniques are varied, some direct and some indirect.

Tension: It can be determined by strain gages, and the resistance will change as the length increases. Changes in resistance measured by these gauges can be converted into forces, so they are indirect devices.

Pressure: Can be determined by the load cell unit. The device can be loaded by detecting a change in cell size under compressive load, or by detecting an increase in pressure within the cell under load, or by a change in resistance under compressive load.

Torsion: Can be considered a combination of tensile and compressive forces, so a combination of the above techniques can be used.

Friction: These conditions involve restricting motion, so friction is detected indirectly by using a combination of force and motion sensors.

3. Tactile sensing

Touch refers to perception through touch. The simplest touch sensors use a simple array of touch sensors, often referred to as matrix sensors.

Each individual sensor is activated upon contact with an object. Determined by detecting which sensors are active (digital) or the magnitude of the output signal (analog). The imprint is then compared to previously stored imprint information to determine the size or shape of the part.

4. Thermal induction

Thermal induction may be required as part of process control or as a means of safety control. There are several methods to choose from, which depend greatly on the temperature of the test.

Commonly used methods are: bimetal, thermocouple, resistance thermometer or thermistor. Thermal imaging cameras can be used in more complex systems involving low-level heat sources.

5. Sound sensor

Acoustic sensors can sometimes detect and differentiate between different sounds. They can be used for speech recognition to issue voice commands or to identify unusual sounds, such as explosions. The most common acoustic sensor is a microphone. An obvious problem with acoustic sensors in industrial environments is the presence of background noise. Acoustic sensors can be easily tuned to respond only to specific frequencies to distinguish between different types of noise.

6. Gas induction

Gas or smoke sensors that are sensitive to certain gases rely on chemical changes in the materials contained in the sensor, causing physical expansion or generating enough heat to trigger a switchgear.

7. Robot Vision Sensing

Vision is probably the most active area of robotic feedback research. Robot vision refers to the use of cameras to capture and convert images in real time into a form that computer systems can analyze. This conversion usually means converting the image into a digital field that the computer can understand. The entire process of image acquisition, digitization, and data analysis should be fast enough so that the robotic system can respond to the analyzed images and take appropriate actions during the execution of the task set.

Improvements in robot vision will unleash the full potential of artificial intelligence in industrial robots. Its purposes include detecting presence, position and movement, identifying and identifying different components, styles and characteristics.

However, even the simplest vision techniques require large amounts of computer memory and require considerable processing time. Generally speaking, there are many kinds of sensing methods of sensors. With the advancement of science and technology, the application of sensors will be more flexible and intelligent.