Measures the acceleration (rate of change in velocity) . Accelerometer sensors uses piezo-electric or MEMS based technologies for sensing. The MEMS based accelerometer sensor is useful in wearable based assist device for measuring various body and hand movements. For measuring tilt using earth’s gravity, a +/-1.5g accelerometer is enough. To measure motion of vehicles, plan or robot, +/-2g accelerometer gives enough headroom. For sudden start, fall and stop movement measurements, more than +/-5g accelerometer is required.
The gyroscope, or gyro for short, adds an additional dimension to the information supplied by the accelerometer by tracking rotation or twist by measuring angular velocity about an axis. There are three basic types of gyroscope:
Gyroscopes in consumer electronics are frequently combined with accelerometers for more robust direction and motion sensing applications.
- Rotary (classical) gyroscopes
- Vibrating Structure (MEMS based) Gyroscope
- Optical (laser based) Gyroscopes
|| The magnetometer measures magnetic flux density value in a specific direction in 3 dimensional space. A magnetometer is capable of detecting fluctuations in the Earth's field and hence used as e-compass in electronic devices so that the device knows which way is North. Useful for measuring orientation of devices in relation to earth’s magnetic field. There are different types of magnetometer:
- Coil Magnetometer
- Hall Sensors
- MEMS based
- Magnetoresistive sensors
- Magnetostrictive sensors
Vibration sensors measure linear velocity or displacement (i.e acceleration). Useful with industrial machines as machine condition monitoring sensors for detecting abnormal vibrations for early detection & repair of machine failures. The severity of machine vibration is standardized by the International Standards Organization (ISO) in the ISO 20816
Or ISO 10816 publications.
The audible noise monitoring sensor measure sound levels in the environment and is useful for sound environment management. By using acoustic pattern classification algorithms, this sensor can map the measured sound level to different noise sources and can automatically detect the target noise source and sound intensity level in dB.
The Temperature sensor measures temperature either through direct contact with the heating source, or remotely, without direct contact with the heating source using radiated energy instead. There are a wide variety of temperature sensors on the market today, including Thermocouples, Resistance Temperature Detectors (RTDs), Thermistors, Infrared, and Semiconductor Sensors.
||Humidity sensor measures the presence of water (moisture) in air. The sensor works with either capacitive sensing principle or uses resistive effects. The amount of water vapour in air can affect human comfort as well as many manufacturing processes in industries. Most commonly used units for humidity measurement are Relative Humidity (RH), Dew/Frost point (D/F PT) and Parts Per Million (PPM). RH is a function of temperature, and thus it is a relative measurement. Dew/Frost point is a function of the pressure of the gas but is independent of temperature and is therefore defined as absolute humidity measurement. PPM is also an absolute measurement.
| Fluid property
|| A fluid property sensor (FPS) based is used to measure the contaminant level of lubricant oil. Oil density, dielectric constant, viscosity, and temperature can simultaneously be measured by this sensor. A typical FPS can measure the value of density ranging from 0 to 115 g/cm3, dielectric constant ranging from 1100 to 6100, viscosity ranging from 0 to 5011 cp, and temperature ranging from −40 to 150°C.
A pressure sensor is a device for pressure measurement of gases, liquids, solid bodies or vapours and is measured in terms of force per unit area. The pressure sensor has a sensing element of constant area and responds to force applied to this area by fluid pressure. The force applied will deflect the diaphragm (made of stainless steel or silicon) inside the pressure sensor and the deflection of this diaphragm is measured as pressure. The most commonly used pressure units are Pa (Pascal), Bar or PSI (Per Square Inch).
A position sensor measures absolute position sensor or a relative one (displacement sensor). The position sensors can be linear, angular, or multi-axis. The position sensors use different sensing principles to sense the displacement of a body.
- Potentiometric sensor
- Inductive (LVDT) sensor
- Rotary encoders
- Capacitive sensor
- Optical position (with incremental encoder) sensor
- Magnetostrictive sensor
|| A level sensor used to measure the level of substances like liquids, slurries, granular materials in a container. This level sensor value is used to determine the amount of materials within a container. The level sensor uses different sensing principles.
- Ultrasonic sensor
- Microwave radar sensor
- Capacitance sensor
- Conductivity/Resistance sensor
- Float switch sensor
- Optical Level switch
A force sensor is used to measure the applied load and weight. A force sensing resistor is special resistor that resistance can be varied by varying by the force applied to it. The strain gauges and capacitive force sensors are used as force sensors. In strain gauge, when a force is applied to the sensor material, it will deform elastically. The strain gauge is used to measure how much the material has deformed by detecting its change in resistance.
|| A flow sensor is used to measure the flow rate of liquid, gas or vapour in a pipe. There are many different technologies used in the measurement of flow.
The choice of the most suitable type depends on a wide range of factors including the nature and viscosity of the fluid, the flow rate range and the accuracy of measurement required
- Differential pressure flow meter
- Electromagnetic flow meter
- Ultrasonic flow meter (Dopler)
- Thermal mass flow meter
- Vortex flow meter
- Coriolis flow meter
- Turbine flow meter (mechanical)
| Voltage and Current
||This is energy sensor that measures electric current and voltage in an AC or DC current levels in electrical wires. The current sensor uses following technologies.
The voltage sensor uses following technologies.
- Hall effect sensor
- Inductive (current coil) sensor
- Series resistor sensor
- Magnetoresistive sensor
- Capacitive divider
- Resistive divider
|| Air quality sensor measures air pollution level by measuring ambient concentrations of air pollutants in air, e.g., NO, NO2, O3, CO2, CO, SO2, CH4, VOC, organic species (benzene, tolulene, formaldehyde), Particulate Matter (PM) mass in one or more size ranges and components of PM, e.g., black carbon.