1. CMPE 118 MECHATRONICS Introduction to Sensors Or, How the world gets into our programs

2. CMPE 118 MECHATRONICS Mechatronic Systems Decision Making Actuation World to Signal The WorldThe World MicroController

3. CMPE 118 MECHATRONICS The World to Signal Sensors or Transducers Convert one physical phenomenon to another Examples that you Encounter Daily Signal Conditioning Match sensor output to the microcontroller’s input

4. CMPE 118 MECHATRONICS

5. Operational Amplifier

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8. What can the Microcontroller Measure ? Hint: Only 2 things Time Every Microcontroller can measure the passage of time If necessary purely with software Voltage Microcontrollers with an Analog to Digital converter (A/D)

9. CMPE 118 MECHATRONICS What can the Microcontroller Measure ?

10. CMPE 118 MECHATRONICS Basic Sensors: Light PhotoCells CdS Resistance Varies with Incident Light More Light = Lower Resistance Spectral Response Approximates Human Eye Dynamic Response Power Rating

11. CMPE 118 MECHATRONICS CdS Photocell Specifications

12. CMPE 118 MECHATRONICS CdS Photocells: How do you use them? In a voltage divider to generate a voltage Anywhere you can use a resistor to vary a circuit’s output Does that suggest another possible circuit?

13. CMPE 118 MECHATRONICS How else could you use a Photocell?

14. CMPE 118 MECHATRONICS Basic Sensors: Light Photo-Transistors NPN only Light Replaces the base current Spectral Response Dynamic Response

15. CMPE 118 MECHATRONICS Directional Characteristics Sensitivity/Linearity

16. CMPE 118 MECHATRONICS LTR3208E Data Sheet

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18. Phototransistors: How Do You Use Them? Simple Ways

19. CMPE 118 MECHATRONICS Phototransistors: How Do You Use Them? Better Way

20. CMPE 118 MECHATRONICS Basic Sensors: Magnetic Field Simplest: Reed Switch

21. CMPE 118 MECHATRONICS Basic Sensors: Magnetic Field Hall Sensors Semiconductors Switches Analog

22. CMPE 118 MECHATRONICS Uni-Polar BiPolar Linear

23. CMPE 118 MECHATRONICS Linear Output Sensor Measuring Rotation Digital Output Sensor Using Bias Magnet

24. CMPE 118 MECHATRONICS Measuring Position Translate Movement to ??? To Voltage What are examples of ???

25. CMPE 118 MECHATRONICS Optical Sensors for Position Reflective

26. CMPE 118 MECHATRONICS Optical Sensors for Position Transmissive

27. CMPE 118 MECHATRONICS Encoders For Position Sensing Combine the Transmissive Optical Sensor With a rotating Mask

28. CMPE 118 MECHATRONICS Encoder: How it works Quadrature

29. CMPE 118 MECHATRONICS Encoders: Where Do You Find Them? Printers Disk Drives

30. CMPE 118 MECHATRONICS Basic Sensors: Temperature Thermistors Large  R for  T Non-Linear But well understood Temperature Sensitive Resistor

31. CMPE 118 MECHATRONICS Basic Sensors: Temperature Platinuum Restive Temperature Devices RTDs Wide Temperature Range Extremely Linear Very Stable Not Very Sensitive

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33. Limited Range of Resistances  R proportional to R at 0  C

34. CMPE 118 MECHATRONICS Basic Sensors: Light Photo-Diodes Spectral Sensitivity Speed Light Sensitivity

35. CMPE 118 MECHATRONICS Wide Dynamic Range

36. CMPE 118 MECHATRONICS

37. LTR516AD Data Sheet

38. CMPE 118 MECHATRONICS Photodiodes: how Do You Use Them?