Sensors
Table of Contents
| Various Sensors |
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What are Sensors?
Sensors are devices that respond to physical stimulus (such as sound, pressure, heat, particular motion etc. )and output a resulting impulse[1].
The output is generally a signal that is converted to human-readable display at the sensor location or transmitted electronically over a network for reading or further processing [2].
Sensor Detecting an Object |
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Characteristics of Sensors
Digital or Analog Sensors
Digital
The sensors sense external parameters such as wind and it outputs discrete values (0 and 1’s), commonly known as binary signals
Analog
The sensor also sense external parameters and it outputs an analog voltage that might be between 0v and 5v. The signal is also continuous and proportional to the measurand
Range
The maximum and minimum values that the sensor can measure (e.x -40 oC to 500 oC)
Accuracy
It is the ability of the sensor to measure a value that is close to the true value of the measured quantity
It is measured by its absolute or relative error
Absolute error = Result -true value
Relative error = Absolute value/true value
Linearity
This relates to the closeness of the calibration curve to the specified straight line.
For example, the theoretical behaviour, least-squares fit
Sensitivity
It is the slope of a calibration curve. An ideal sensor would have a large and constant sensitivity
A non-linear function exhibits different sensitivity at different points. The first derivative is taken to give us the slope of the sensor whose function is non-linear.
Application of Sensors
1.Automotive
Sensors play an important role in both the manufacturing and operation of vehicles. Due to advancements in technology, modern cars have an even more complex set up of sensors. In the manufacturing process of cars, there are robotic arms containing sensors used to paint the body of cars. The thickness of the paint is also measured using sensors.
The Electronic control unit (ECU) houses all the hardware and software of the car. Data received from various sensors are processed here. Some common sensors found in cars are listed below.
| Sensors found in cars |
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Tesla uses ultrasonic sensors to detect cars close by which is needed for semi-autonomous self driving. It also increases safety as it can help prevent collisions.
| Ultrasonic sensors used in a Tesla |
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2. Manufacturing
Sensors play a very important role in the operation of many manufacturing plants as well as the improvement of the efficiency of manufacturing processes. For instance, a temperature and vibration sensor can help detect if a machine is running irregularly. This provides predictive maintenance. Another application is in quality control. Various manufacturing parameters such as thickness, humidity and even protein can be monitored.
| Sensors used to measure thickness |
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3. Aviation
During a flight, feedback on flight conditions and aircraft equipment are required to ensure the safe operation of the airplane. For example, flow sensors monitor the amount of lubricating oil, liquid coolant and other fluid moving in the system. Liquid level sensors check fuel, oil and coolant levels. Pressure sensors monitor pressure in hydraulic systems. This is very important as these systems are essential in landing and braking the plane.
| Sensors in an aircraft |
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4. Medical and Healthcare
Data collected from sensors in medical equipment and surgical devices are used by medical practitioners in diagnosis, treatment and control functions. Apart from equipment, sensors can also monitor the internal workings of patients during procedures. Some examples include glucose monitoring, robotics driven operations and automatic detection of visitors spreading disease to hospital patients.
| Sensors used in the Medical Field |
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Smart watches provide a very easy way to keep track of one's health. Motion sensors are able to detect the number of steps and physical movement a person does in a day. An optical heart rate sensor helps monitor blood flow by detecting the pulse in one's wrist. This data is used to calculate heart beats per minute. Some watches are able to detect irregular heart patterns and alert relevant medical authorities based on this data.
| Sensors in a Smart watch |
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Sensors Use Cases
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Boiler Pressure Sensors | Sensors are Used to Measure Body Temperature |
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References
[1] "Definition of SENSOR", Merriam-webster.com, 2020. [Online]. Available: https://www.merriam-webster.com/dictionary/sensor. [Accessed: 03- Nov- 2020].
[2] K. Al-Aubidy, "Sensor Characteristics", Philadelphia.edu.jo, 2020. [Online]. Available: https://www.philadelphia.edu.jo/academics/kaubaidy/uploads/Sensor-Lect2.pdf. [Accessed: 03- Nov- 2020].
[3] How to Electronics, "Top 15 Latest Sensor Projects for Arduino Begineers", Youtube.com, 2020. [Online]. Available: https://www.youtube.com/watch?v=NePXqRwvmbs&app=desktop&ab_channel=HowToElectronics. [Accessed: 03- Nov- 2020].
[4] Illinois Tech, "Sensors: Types and Characteristics", Web.iit.edu, 2020. [Online]. Available: https://web.iit.edu/sites/web/files/departments/academic-affairs/academic-resource-center/pdfs/SENSORS.pdf. [Accessed: 03- Nov- 2020].
[5] RealPars, "What is a Pressure Sensor? | Types of Pressure Sensors | RealPars", PLC Programming Courses for Beginners | RealPars, 2020. [Online]. Available: https://realpars.com/pressure-sensor/. [Accessed: 03- Nov- 2020].
[6] "What is sensor? - Definition from WhatIs.com", WhatIs.com, 2020. [Online]. Available: https://whatis.techtarget.com/definition/sensor. [Accessed: 03- Nov- 2020].
Contributors:
| User | Last Update |
|---|---|
| Mayurakhi Khan | 936 days ago |
| m426khan@uwaterloo.ca |