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1. SENSOR TECHNOLOGY Department of Civil Engineering

2. Course Outcomes Course outcomes: At the end of the course, students will be able to BCE-DS-322.1 Understand sensor fundamentals and selection criteria BCE-DS-322.2 Apply sensor principles and applications BCE-DS-322.3 Analyze intelligent sensor systems and emerging trends BCE-DS-322.4 Evaluate virtual instrumentation techniques

3. Chapters Unit 1: Sensors and Transducer Unit 2: Measurement of temperature using Thermistor Unit 3: Virtual Instrumentation Unit 4: Data Acquisition Methods Unit 5 : Intelligent Sensor Unit 6: Case Studies and Emerging Trends

4. Sensors According to Instrument Society of America: A sensor is a device which provides a usable output in response to a specified measurand . The output is defined as an electrical quantity and measurand as a physical quantity or condition or property which is measured.

5. Sensor Sensors  are sophisticated devices that are frequently used to detect and respond to electrical or optical signals. A Sensor  converts the physical parameter (for example: temperature, blood pressure, humidity, speed, etc.) into a signal which can be measured electrically.

6. Sensor The sensor is a device that measures the physical quantity (i.e. Heat, light, sound, etc.) into an easily readable signal (voltage, current etc.). It gives accurate readings after calibration.

7. Example Examples – The mercury used in the thermometer converts the measurand temperature into an expansion and contraction of the liquid which is easily measured with the help of a calibrated glass tube. The thermocouple also converts the temperature to an output voltage which is measured by the thermometer.

8. Example

9. Examples The sensors have many applications in the electronics equipment. The few of them are explained below: The motion sensors are used in the home security system and the automation door system. The photo sensor senses the infrared or ultraviolet light. The accelerometer sensor is used in the mobile for detecting the screen rotations.

10. What are some quantities that can be sensed? Motion, position, displacement Velocity and acceleration Force, strain Pressure Flow Sound Moisture Light Radiation Temperature Chemical presence

11. The Response is an Electrical Signal When we say electrical we mean a signal which can be channeled, amplified and modified by electronic devices: Voltage Current Charge The voltage, current or charge may be described by: Amplitude Frequency Phase Digital code

12. Transducers: sensors and actuators Transducer A device that converts a signal from one physical form to a corresponding signal having a different physical form Physical form: mechanical, thermal, magnetic, electric, optical, chemical… Transducers are ENERGY CONVERTERS or MODIFIERS Sensor A device that receives and responds to a signal or stimulus This is a broader concept that includes the extension of our perception capabilities to acquire information about physical quantities Transducers: sensors and actuators Sensor: an input transducer (i.e., a microphone) Actuator: an output transducer (i.e., a loudspeaker) Sensor Processor Actuator Input transducer Output transducer Input s i gnal (mea s u r an d ) Output signal (mea s u r an d ) 12

13. Transducer The transducer is a device that changes the physical attributes of the non-electrical signal into an electrical signal which is easily measurable. The process of energy conversion in the transducer is known as the transduction. The transduction is completed into two steps: First by sensing the signal and then strengthening it for further processing.

14. Transducer The transducer has three major components: They are the input device, signal conditioning or processing device and an output device. The input devices receives the measurand quantity and transfer the proportional analogue signal to the conditioning device. The conditioning device is modified, filtered, or attenuates the signal which is easily acceptable by the output devices.

15. Example

16. Sensor & Transducer A sensor senses the physical changes that occur in the surrounding whereas Transducer converts the physical or non electrical quantity into electrical signal.

17. Difference One of the significant difference between the sensor and the transducer is that the sensor senses the physical changes occuring in the surroundings whereas the transducer converts the physical quantity or nonelectrical quantity into an electrical signal.

18. Difference The sensor detects the energy level and changes it into an electrical signal which is easily measured by the digital meters. The transducer transfers the energy either in the same form or another.

19. Comparison Chart