1. Module 4: Proximity Sensors Eng. Asma Abu Baker

2. Outlines Analog Sensors Digital Sensors Proximity sensors Inductive sensor Capacitive sensor Optical sensor Ultrasonic sensor

3. Recap Definition: senses the input physical variable and converts it into a measurable signal Sensor / transducerNamePhysical variableMeasurable signal

4. Proximity sensors 1. Ultrasonic Sensor2. Optical sensor 3. Inductive sensor4. Capacitive sensor

5. Ultrasonic proximity sensor can detect solid, liquid, granular and powdery substances

6. Ultrasonic sensor application Detect the object within a specified range. Detection range almost 100 cm measure the distances of the nearby car Detecting the presence of a person Detect the presence of the car

7. Ultrasonic sensor application Sensing Liquid LevelsControl of lifting vehicles

8. Optical proximity sensors Optical proximity sensors are used for counting boxes, breakage and jam detection Almost 10 cm detection range

9. Inductive proximity sensors Inductive proximity sensors are used to detect the presence of metals Detection range is very small.

10. Capacitive proximity sensors Capacitive proximity sensors are used to detect metallic and non-metallic objects such as wood, paper, liquid and so on. Detection range is very small.

11. Counting Application

12. Types of sensors Binary / Digital sensor (switches) – Output has two values only Analog sensors – Output has many values : Range

13. Temperature o C Thermocouple output 25 o C0.1 mv 30 o C0.3 mv 35 o C0.6 mv 40 o C0.9 mv 45 o C1 mv 50 o C1.3 mv 55 o C1.5 mv Does the thermocouple have only two values or many values ? Many values, then its analog sensor

14. Temperature o C RTD output 30 o C0.114 kΩ 35 o C0.116 kΩ 40 o C0.118 kΩ 45 o C0.12 kΩ 50 o C0.122 kΩ 55 o C0.124 kΩ 60 o C0.125 kΩ Does the RTD have only two values or many values ? Many values, then its analog sensor

15. Temperature o C Thermister output k Ω 251.4 301.1 350.99 400.82 450.7 500.6 550.51 Does the thermistor have only two values or many values ? Many values, then its analog sensor

16. Binary sensors, optical sensor How many values I am reading ? Two values, then its binary sensor

17. Binary sensors, Optical sensor Physical variableMeasureable signal Object exist0 volts Object don’t exist24 volts

18. Analog sensors, Ultrasonic sensor How many values I am reading ?

19. Sensors can operate – by contact – Without contact (Proximity sensors ) They are selected based on the application. Is this sensor operates by contact, or without contact ?

20. Advantages of contactless proximity sensor Precise and automatic sensing of position. Contactless sensing protects objects from damage. Fast response, and do not include moving parts which can wear out.

21. Lab Activity 1 Don’t switch on the power supply till I check the circuit for you

22. Select Pulse The clock is S2

23. Lab Activity 1 1.Connect Optical sensor 2.Connect inductive sensor

24. Conclusion Proximity sensors Proximity sensors application Analog and digital sensors