Why use vibration sensors in IoT systems
The reason for using vibration sensors in IoT systems is mainly based on their application value and functional characteristics in many aspects. The following is a specific analysis of the reasons:
1. Real-time monitoring and early warning
Security monitoring:
Vibration sensors can be installed in vulnerable places such as walls, doors and windows to monitor illegal intrusions or sabotage activities. When it is detected that the vibration of the surrounding environment exceeds the set threshold, an alarm will be triggered to notify security personnel or owners to handle it in a timely manner, thereby enhancing safety.
Natural disaster warning:
When natural disasters such as earthquakes and storms occur, vibration sensors can detect strong vibrations and trigger alarms, providing important early warning information for disaster prevention and reduction .
2. Equipment status monitoring and maintenance
Industrial equipment monitoring: Vibration sensors are widely used in vibration monitoring of rotating equipment such as motors , reducers, fans, and generators . By monitoring the vibration of equipment in real time, equipment faults or abnormalities can be discovered in time, equipment damage can be prevented, and production efficiency and equipment service life can be improved.
Building structure monitoring: In the construction industry, vibration sensors can be installed in various parts of the building, such as walls, floors and beams, to monitor the vibration of the building. This helps to understand the structural condition of the building, identify potential safety hazards in a timely manner, and make repairs or replacements if necessary.
Equipment status monitoring:
The detection method of vibration switch is non-intrusive detection and will not affect the normal operation of the equipment. This makes vibration switches have broad application prospects in equipment condition monitoring.
Example 1: Application of ball switch vibration sensor: When monitoring the status of barrel equipment, the vibration sensor is installed on the barrel cover. During the opening and closing process of the barrel cover, due to the change in the tilt angle of the barrel cover, the ball of the vibration sensor is connected to the vibration sensor. The two electrodes generate trigger signals .
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Example 2: Dumbbell core ball vibration sensor, used for various vibration triggering functions, theft alarm, smart car, earthquake alarm, truck alarm, etc. Compared with the normally open vibration sensor module, this module has a longer vibration triggering time and can drive the relay module. The principle is shown in the figure below: When there is no vibration, the vibration shaft is in a stationary state, and the ends of guide pin A and guide pin B are connected. When there is vibration, the vibration shaft will move, and the gap between guide pin A and guide pin B There will be a momentary disconnection to achieve the function of vibration triggering.
3. Environmental monitoring and data analysis
Geological exploration: Vibration sensors can be used to measure vibrations on the ground to help understand the conditions of underground materials, such as searching for oil, gas or mineral resources. In addition, it can also be used to monitor earthquakes and other geological disasters and provide data support for disaster prevention and reduction.
Traffic monitoring: Vibration sensors can be installed on roads, bridges and rail transit facilities to monitor cracks and deformations of road surfaces and vibrations of transportation vehicles to improve the safety and comfort of transportation facilities.
4. High precision and low power consumption
High-precision measurement: Modern vibration sensors use high-performance MEMS chips and advanced sensing technology , which have the characteristics of high precision, high sensitivity and high stability, and can accurately measure various vibration parameters .
Low-power design : In order to meet the needs of the Internet of Things system, vibration sensors usually adopt low-power design, which extends the battery life of the device and reduces the cost of use.
To sum up, the reasons for using vibration sensors in IoT systems mainly include the advantages of real-time monitoring and early warning, equipment status monitoring and maintenance, environmental monitoring and data analysis, as well as high accuracy and low power consumption. These advantages make vibration sensors play an increasingly important role in IoT systems and promote the continuous development and innovation of IoT technology.
This article will give you a detailed explanation of one member of the sensor family – the vibration sensor.
Vibration sensor definition
A vibration sensor, also known as a vibration sensor, is a device used to measure and detect vibrations of mechanical equipment or structures. It can convert vibration motion into electrical or other physical quantity signals, and then process and analyze these signals. Vibration sensors usually consist of sensitive components, signal amplifiers , and filters that work together to convert mechanical vibrations into measurable electrical signals.
Classification of vibration sensors
Classification according to mechanical receiving principle
Relative vibration sensor:
Principle: Detect vibration based on relative motion between mechanical structures.
Example: The relative electrodynamic sensor among electrodynamic sensors uses a moving conductor to cut magnetic lines of force in a fixed magnetic field to generate electromotive force to measure vibration.
Inertial vibration sensor:
Principle: The principle of inertia is used to detect vibration through the inertial force of the mass block inside the sensor when it vibrates.
Example: An inertial electric sensor consists of a fixed part, a movable part and a supporting spring part. It reflects the vibration situation by measuring the displacement or acceleration of the movable part when it vibrates.
Classification according to electromechanical conversion principle
Electric vibration sensor:
Principle: Based on the principle of electromagnetic induction , it converts mechanical vibration into electrical signals.
Features: The output signal is proportional to the measured vibration speed, suitable for speed measurement.
Piezoelectric vibration sensor:
Principle: Utilize the piezoelectric effect of piezoelectric materials to convert mechanical vibration into electrical signals.
Features: high sensitivity, wide frequency range, high signal-to-noise ratio, widely used in acceleration measurement.
Eddy current vibration sensor:
Principle: Based on the eddy current effect, vibration is detected by measuring the distance change between the sensor and the measured object.
Features: Non-contact measurement, suitable for harsh environments such as high temperature and high speed.
Inductive vibration sensor:
Principle: Using the principle of electromagnetic induction, vibration is detected by measuring the inductance changes caused by vibration.
Features: Simple structure, high reliability, suitable for measuring various parameters such as displacement, velocity, acceleration, etc.
Capacitive Vibration Sensor:
Principle: Vibration is detected by measuring the change in capacitance caused by vibration.
Features: High accuracy and good stability, suitable for measuring parameters such as displacement and frequency.
Resistive Vibration Sensor:
Principle: The resistance value of the resistive material changes with mechanical deformation to detect vibration.
Features: Simple structure, low cost, suitable for some occasions that do not require high accuracy.
Photoelectric vibration sensor:
Principle: Use the photoelectric effect or grating principle to convert mechanical vibration into optical signals and then into electrical signals.
Features: non-contact measurement, high accuracy, suitable for vibration measurement in some special environments.
Classification according to measured mechanical quantities
Displacement sensor: directly measures the displacement of an object’s vibration.
Speed sensor : measures the speed at which an object vibrates.
Acceleration sensor : measures the acceleration of the vibration of an object and is the most commonly used sensor in vibration measurement.
Force sensor: measures the force generated during vibration.
Strain sensor : reflects the vibration situation by measuring the strain of the object during vibration.
Torsional vibration sensor: A sensor specifically designed to measure torsional vibration.
Torque sensor : measures the torque generated during vibration
The principle of vibration sensor
Basic principles
Vibration sensors achieve their function by converting the vibration of the measured object into a measurable physical quantity (such as an electrical signal). This conversion process relies on sensitive elements inside the sensor, which can sense the vibration of the object and convert it into a corresponding electrical signal output.
Different types of vibration sensor principles
Piezoelectric vibration sensor
Principle: Based on the piezoelectric effect, that is, certain crystal or ceramic materials generate electric charges when subjected to mechanical stress. When a vibration sensor is vibrated, the piezoelectric material deforms, producing a charge or voltage change. This change is converted into an electrical signal, which is used to measure and analyze the amplitude and frequency of the vibration.
Application: Widely used in industrial manufacturing, structural monitoring and other fields.
Strain Vibration Sensor
Principle: Use the strain properties of materials to measure vibration. Inside the sensor is a metal or elastic rod to which a strain gauge is attached. When an object vibrates, the material becomes strained, causing the strain gauge to produce a change in resistance or voltage. This change is measured and recorded to evaluate vibration intensity and frequency.
Application: Commonly used in scenarios where material strain needs to be measured.
Inductive vibration sensor
Principle: Based on the principle of electromagnetic induction. The sensor consists of a magnetic core, coil and load resistor. When an object vibrates, the position of the core changes relative to the coil, thereby changing the coil’s self-inductance. This change results in a change in the inductance value, and vibration information is obtained by measuring the change in inductance.
Application: Especially suitable for measuring parameters such as acceleration and vibration speed.
capacitive vibration sensor
Principle: Obtain variable capacitance through the change of gap or common area, and then measure the capacitance to obtain mechanical vibration parameters. The variable gap type is mainly used to measure linear vibration displacement, while the variable common area type can be used to measure angular displacement of torsional vibration.
Application: Excellent performance in scenarios that require high-precision measurement of vibration displacement.
Voltage vibration sensor
Principle: Utilize the voltage effect of the crystal. When the vibration of the measured object puts pressure on the sensor , the crystal element will generate a corresponding load and convert it into vibration parameters through the load number.
Application: Used in specific fields such as precision instruments .
Eddy current vibration sensor
Principle: A vibration sensor based on the eddy current effect. The vibration and displacement of the object are measured through the change in distance between the measured object and the top of the sensor.
Application: Because of its non-contact measurement and high sensitivity, it is widely used in vibration displacement measurement.
Vibration sensor workflow
Vibration sensing: The sensitive element inside the sensor senses the vibration of the object being measured.
Signal conversion: Sensitive components convert vibrations into measurable physical quantities (such as charge, voltage, resistance, etc.).
Signal processing: The converted signal undergoes amplification, filtering and other processing to improve the signal-to-noise ratio and accuracy of the signal.
Output display: The processed signal is output in digital or analog form for analysis and monitoring by subsequent equipment.
Vibration sensor parameter selection
When selecting a vibration sensor, there are several selection parameters that need to be considered to ensure that the sensor can meet the specific measurement needs and application environment. Here are some key selection parameters:
Measurement parameters
Physical quantity: Make it clear whether the physical quantity to be measured is acceleration, velocity or displacement. Different types of vibration sensors are suitable for measuring these three different physical quantities.
Measuring range and overload capability
Measuring range or measurement range: The vibration range that the vibration sensor can measure should ensure that its range covers the vibration amplitude range that needs to be measured. For example, some vibration sensors may have a measurement range of 0-50g (a unit of acceleration due to gravity).
Overload capability: The sensor should have a certain overload capability to prevent damage under sudden high vibration shock.
Measurement frequency
Frequency response characteristics: The frequency response range of the sensor should meet the measurement needs. High-frequency vibration requires a sensor with a high frequency response, while low-frequency vibration requires a sensor with a lower frequency response. Generally speaking, the frequency response range of vibration sensors is usually 0.5-10kHz.
Sensitivity
Sensitivity: refers to the response degree of the sensor to vibration signals. The higher the sensitivity of a vibration sensor, means it can detect small changes in vibration earlier. When selecting, the appropriate sensitivity needs to be selected according to the application requirements. Generally, the sensitivity of vibration sensors is 10-100mV/g.
environmental conditions
Temperature , humidity: The sensor should be able to maintain stable performance in the working environment and not be affected by environmental factors such as temperature and humidity. The operating temperature range of vibration sensors is typically -40°C to +85°C.
Corrosiveness and vibration level: For special working environments, such as corrosive media or high vibration level environments, sensors with corresponding protection levels need to be selected.
Signal output mode
Output type: According to the requirements of the subsequent processing system, select the appropriate signal output method, such as voltage signal (0-5V or 0-10V) or current signal (4-20mA).
Static and dynamic characteristics
Static characteristics: Including parameters such as linearity, hysteresis, repeatability, accuracy, resolution, stability and drift, these parameters describe the performance of the sensor under static conditions.
Dynamic characteristics: including parameters such as natural frequency, damping ratio, time constant, rise time, response time, etc. These parameters describe the performance of the sensor under dynamic changes.
reliability index
Working life: The sensor should have sufficient working life to meet the needs of long-term use.
Failure rate: Low failure rate is the key to improving system reliability.
Insulation, voltage resistance, temperature resistance, etc.: The sensor should have good insulation performance, voltage resistance and temperature resistance.
Power supply method
Vibration sensors usually require external power supply, and their power supply voltage is usually 8-36V. When selecting, ensure that the power supply method meets the application requirements and be careful not to exceed the rated voltage of the sensor.
Cost and Maintenance
Cost: On the premise of meeting the measurement needs, choose cost-effective sensors to reduce costs.
Maintenance and calibration: Consider the ease of maintenance and calibration intervals of the sensor to ensure that the sensor can operate stably for a long time.
Precautions for using vibration sensors
Installation location and direction
Location selection: The vibration sensor should be installed on the surface of the equipment that needs to measure vibration, and the location should avoid areas of strong vibration of the equipment, areas where the temperature exceeds the tolerance range of the sensor, etc., to reduce external interference and ensure measurement accuracy.
Directional consistency: Ensure that the sensor installation direction is consistent with the measurement direction to avoid measurement errors caused by direction deviation. The sensor axial sensitivity axis direction should be as consistent as possible with the required measurement direction to maximize axial response and reduce lateral response.
Cable routing and environmental factors
Cable routing: Cables should be routed according to the diagrams or instructions provided by the sensor manufacturer. Avoid placing sensor cables in the same area as high-voltage cables or other strong power sources to reduce electromagnetic interference and ensure signal transmission quality.
Ambient temperature: The measurement range of the vibration sensor is affected by the ambient temperature, so attention should be paid to changes in the installation environment temperature and its impact on the measurement signal. At the same time, select the appropriate working environment temperature range according to the sensor specifications to avoid sensor damage or performance degradation caused by high or low temperatures.
Equipment inspection and safety measures
Equipment Inspection: Always check the condition of the vibration sensor before use. If the equipment is damaged or abnormal, stop using it immediately and repair or replace the equipment in time.
Safety measures: Operators should wear safety gear, use protective equipment, and try to avoid direct contact with equipment. At the same time, pay attention to comply with relevant safety operating procedures and regulations to ensure personal and equipment safety.
Proper operation and regular calibration
Correct operation: Correctly operate the vibration sensor according to the equipment manual and the instructions provided by the manufacturer to avoid measurement errors or equipment damage caused by improper operation.
Regular calibration: The measurement accuracy of the vibration sensor will decrease with time, so regular calibration is required to ensure the accuracy and stability of the sensor. The calibration cycle should be determined based on the actual application conditions and sensor performance requirements. It is generally recommended to calibrate according to the calibration cycle recommended by the manufacturer.
Other things to note
Fix firmly: Ensure that the sensor is firmly fixed to prevent measurement inaccuracy and resonance caused by looseness. During the installation process, attention should be paid to the appropriateness of the bolt tightening torque to avoid installation stiffness problems caused by over-tightening or over-looseness.
Consistency of measuring point locations: When conducting long-term monitoring or multi-point monitoring, the consistency of measuring point locations should be maintained for accurate vibration analysis and fault diagnosis.
Interchangeability: When using multiple sensors for measurement, good interchangeability between sensors should be ensured to reduce measurement errors and improve data comparability.
