1. Embedded Systems Development and Applications Terrence Mak The Chinese University of Hong Kong CENG4480 - 2014/15

2. Sensors Motion (Orientation/inclination) sensors Force/pressure/strain Position Temperature and humidity Rotary position Light and magnetic field sensors 2

3. Motion Acceleration Gyroscope Compass Tilt Sensor Sensors (v.1c) 3

4. Accelerometer http://en.wikipedia.org/wiki/Accelerometer Functions: – Measure acceleration in one or more directions, position can be deduced by integration. – Orientation sensing : tilt sensor – Vibration sensing Methods: – Mass spring method ADXL78 (from Analog Device ) – Air pocket method (MX2125) 4

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6. ADXL78 (from Analog Device) Mass spring type (output acceleration in G) Measure the capacitance to create output 6

7. ADXL330 Accelerometer for three (X,Y,Z) directions 3D 7

8. 2D Translational Accelerometer MX2125 (from www.parallax.com) Gas pocket type When the sensor moves, the temperatures of the 4 sensors are used to evaluate the 2D accelerations 8

9. Accelerometer: Orientation Sensing 9 http://www.youtube.com/watch?v=9NEiBDBXFEQ Sensor demo

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11. Accelerometer: Tilt sensing demo 11 http://www.youtube.com/watch?v=C6uVrYz-j70 Tilt sensing demo

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13. Sensors (v.1c) 13

14. Gyroscopes http://en.wikipedia.org/wiki/Gyroscope Gyroscope – Measure rotational angle Rate Gyroscope – measure the rate of rotation along 3-axes of X (pitch), Y (roll), and Z (yaw). – Modern implementations are using Microelectromechanical systems (MEMS) technologies. 14 Gyroscope

15. Gyroscope to measure Rational acceleration ADXRS401 http://www.analog.com/UploadedFiles/Data_Sheets/ADXRS401.pdf FEATURES – Complete rate gyroscope on a single chip Microelectromechanical systems (MEMS) – Z-axis (yaw-rate) response APPLICATIONS – GPS navigation systems – Image stabilization – Inertial measurement units – Platform stabilization 15

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17. Compass-- the Philips KMZ51 magnetic field sensor 50/60Hz (high) operation, a jitter of around 1.5° 17

18. Rate gyroscope demo 18 http://www.youtube.com/watch?v=VP4-wdMMLFo Using Gyroscope compass for virtual reality application in an iphone

19. Tilt Sensor by OMRON http://rocky.digikey.com/WebLib/Omron%20Web%20Data/D6B.pdf Detect tilting 35 ~ 65 degrees in right-and-left inclination 19

20. Force, Pressure and Strain Force-sensitive resistor (FSR) Strain gauge Flexion Air pressure 20

21. Force Sensing Resistors http://www.interlinkelectronics.com/library/media/papers/pdf/fsrguide.pdf FSR402 Sensors (v.1c) 21

22. Force Sensing Resistor Demo 22 http://www.youtube.com/watch?v=LQ21lXr6egs

23. Application for a walking robot Walking robot 23

24. Application of force sensing resistance sensors to balance a walking robot Balancing 24 Floor tilled right upper leg bend left Floor tilled left upper leg bend right Neutral position Four sensors under the foot

25. Four Force sensors under the foot 25

26. Strain Gauge : Force sensors http://www.meas-spec.com/myMeas/default/index.asp Piezoelectric crystal: produces a voltage that is proportional to force applied Strain gauge: cemented on a rod. One end of the rod is fixed, force is applied to the other end. The resistance of the gauge will change with the force. 26

27. Sensors (v.1c) 27

28. Single element strain gauge sensitive to temperature change. 28 VbVb R R R Gauge=R+  R gauge load rod V0V0

29. Four-element (Wheatstone bridge) strain gauge sensor, Four times more sensitive than single gauge system; not sensitive to temperature change. All gauges have unstrained resistance R. 29 b1=R-  R t2=R+  R b2=R-  R t1=R+  R VbVb t1 t2 b1 b2 rod load V0V0

30. Flexion (bend) sensors Resistance 10 KΩ (0°) 30-40 KΩ (90°) Sensors (v.1c) 30 http://www.flexpoint.com/ http://www.jameco.com/wcsstore/Jameco/Products/ProdDS/150551.PDF

31. Felixon resistance Demo 31 http://www.youtube.com/watch?v=m4E5SP7HCnk&feature=related

32. Air pressure sensor Measure up to 150 psi (pressure per square inch). 32

33. Position sensors Infra-red range sensor Linear and Rotary position sensors 33

34. Infra-red Range detectors by SHARP (4 to 30cm) An emitter sends out light pulses. A small linear CCD array receives reflected light. The distance corresponds to the triangle formed. Sensors (v.1c) 34

35. IR radar using the Sharp range detector 35 http://www.youtube.com/watch?v=tStBLAiQaC8&feature=related

36. Position sensors RotaryLinear Optical shaft encoder 36

37. Magnetic rotary encoder (http://www.renishaw.com/UserFiles/acrobat/UKEnglish/L-9517-9147.pdf) Non-touch sensing 37

38. Optical rotary encoder (http://en.wikipedia.org/wiki/Rotary_encoder) The light received (on or off) will tell the rotation angle) Sensors (v.1c) 38 3 light emitters 3 light receivers Rotation shaft Light paths http://www.youtube.com/watch?v=RuIislTGOwA Crank shaft sensor

39. Temperature and humidity Temperature Humidity Sensors (v.1c) 39

40. Temperature Sensors http://www.national.com/pf/LM/LM135.html Directly calibrated in °Kelvin 1°C initial accuracy available Operates from 400 µA to 5 mA Less than 1 Ohm dynamic impedance Easily calibrated Wide operating temperature range 200°C over range Low cost 40

41. Application note 41

42. Leaf Sensor Alerts When Plants Are Thirsty Sensors (v.1c) 42 http://www.youtube.com/watch?v=VM4X_fqPPco

43. TSL250, TSL251, TSL252 LIGHT-TO-VOLTAGE OPTICAL SENSORS http://focus.ti.com/general/docs/scproducts.jsp Light-to-voltage optical sensors, each combining a photodiode and an amplifier (feedback resistor = 16 MW, 8 MW, and 2 MW respectively). The output voltage is directly proportional to the light intensity on the photodiode. 43

44. Cadmium Sulfoselenide (CdS) Photoconductive Photocells http://faculty.uml.edu/aelbirt/16.480/pdvp5001.pdf Light sensing using CdS 44

45. Hall effect Sensors for sensing magnetic flux “B field” http://doc.semicon.toshiba.co.jp/noseek/us/td/td2frame.htm 45

46. Application on Magnetic levitation 磁懸浮 http://myweb.msoe.edu/~muthuswamy/pubs/DesignOfMagneticLevitationControllersUsingJacobiLinearizationFeedbackLinearizationAndSlidingMode.pdf 46 http://www.youtube.com/watch?v=XjjBqzilkIc Magnetic levitation Train Model 磁懸浮火車 http://www.youtube.com/watch?v=TeS_U9qFg7Y frog levitation http://www.youtube.com/watch?v=A1vyB-O5i6E

47. Hall effect sensors and brushless DC motors Brushless DC motor http://dev.emcelettronica.com/files/u4/Brushless_DC_Motors_bldc_motor.jpg Is it using Hall effect sensor? Don't known. 47 http://www.youtube.com/watch?v=JmRkxZT4XhY http://www.youtube.com/watch?v=cm0h2Qf3upQ

48. Novel sensors Kinect 48 http://www.youtube.com/watch?v=nvvQJxgykcU http://www.youtube.com/watch?v=Mf44bWQr3jc http://www.ladyada.net/learn/diykinect/

49. Many KINECT DIY projects 49 http://www.youtube.com/watch?v=Brpu30vjCa4&feature=related http://www.youtube.com/watch?v=3V-TGXFZbbA&feature=related

50. Sensors (v.1c) 50

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52. Sensors (v.1c) 52