Wireless Sensor Module For Structural Health Monitoring of Composites in Aircraft

1. Wireless Sensor Module For Structural Health Monitoring of Composites in Aircraft Team 3 Sponsors: SPIRIT � Dr. Farhad Tadayon, Ken Loomis CEAM � Prof. Sia Nemat-Nasser UCSD � Mr. Jon Isaacs Team 3 Members: Chris Beltran Channa Bou Soheil Banisadr 1

2. Agenda Statement of Work Composites Wireless Sensor Network Active System Zigbee Protocol Changes from Original Plan Hardships Successes Future Work Gantt Chart 2

3. Statement of Work (Original) To design and assemble a Wireless Sensor Network utilizing the Zigbee protocol that is an improvement on the previous quarter's design. This network will monitor the physical health of an aircraft by placing multiple acoustic sensors throughout its composite structure. We aim to address such problems faced by the previous quarter such as bandwidth limitations, timing issues, real-time data acquisition issues, and low data transfer rates. 3

4. Statement of Work (revised as of 1/23/09) Deter from seeking faults in composite material (complexity and time constraint of class) Focus and establish communication and transfer of data from one mote to another Use previous quarter�s development kit (Crossbow) Due to time constraint Determine distances of wave travel Done using clocking techniques from PIC clock 4

5. Wireless Sensor Network Network of devices that contain sensors that monitor physical or environmental conditions such as sound, vibrations, pressure, etc. Each sensor mote is equipped with a wireless communication device, microcontroller, ADC, and energy source. 5

6. Zigbee Wireless Protocol Near-guaranteed message delivery Mesh routing and route discovery algorithms Large-scale network integration Minimal design and development effort Supports fault tolerant multi-hop mesh networks Low Power Consumption 6

7. Crossbow - Starter Kit Benefits: High Speed (250 kbps) Hardware security(AES 128) Reliable Networking Software for Self- forming, Self-healing Mesh Networks (Xmesh) 7

8. The Big Picture 8

9. Distance Detection 9

10. Tx/Rx Layout From the Module 10

11. Charge Amplifier 11

12. Transducer 12

13. Piezo Driver For a Piezo Crystal to be excited we need high voltage ( may be as high as 60V-100V) Experiment showed piezo film is excitable at 10Vpp. Only have 3V from AA battery so need a charge pump (DC/DC converter) to step-up voltage Also need to provide the oscillation frequency that would be used to emit from PVDF Proposed idea is a Dickson Charge Pump 13

14. Piezo Driver (cont.) 14

15. Piezo Driver (Cont.) 15

16. Proposed Oscillating technique The voltage from the Q-pump will be attached in the following configuration When MOSFET turned on, Vout will be 0 and when MOSFET is turned off, Vout will be high. The clock will be controlled by a PIC which will perform in a pulsing fashion. 16

17. Recent work (Previous weekend) No labels on Q-Amp, so time was taken to figure out which input corresponded with which output. Signals were very noisy Might need to be addressed � filters? Every time the wires were moved around the signal on the oscilloscope would change, but frequency was still found. 17

18. Recent work (Previous weekend) 18

19. Recent work (Previous weekend) 19

20. Weekend Plan Meet Mr. Jon Isaacs about project Find Q-Amp documentation in his lab Determine Frequency of transmission for Piezo film Verify the that input and output time difference gives the correct distance. Checks the wave velocity of fiberglass Interfacing Piezo with Xbow via blank sensor board Familarize with PIC microcontroller Write program for �hello world� Range testing for mote networks. 20

21. PIC driven TX signal Limitations from Mote data transfer to Gateway: Can only transmit 10Hz of raw data (too slow) Proposed Solution: PIC microcontroller PIC sets initial Tx wave time into a register. Records Rx wave time into another reg. Stores the time difference as a # value in PIC register (e.g. 15ns==15) # preprocessed through DAC and associated with specific voltage (e.g. 15==15mV) Analog signal sent from PIC to Gateway Benefit: Easier and faster to send # value than raw analog data 21

22. Future Work Establish delay time from one transducer to another Learn PIC microcontroller programming language Integration of transducers to large scale mesh network From delay time and know ultrasonic velocity of a signal through fiberglass calculate distance 22

23. Hardships Had trouble having a definite goal established in the first few weeks. Charge amplifier is faulty Channel 3 proved to show erratic output signal Signal is not as clean as we would like on the oscilloscope On 1/31/09 failed to establish communication between MTS310CA sensor and MIB510CA Gateway Used MoteView manual to understand how to program motes instead of MoteConfig manual Incompatibility with Vista? Used Windows XP Trouble finding proper USB to Serial Cable Driver 23

24. Successes On 2/2/09 got help with establishing proper connection from (Gabriel) Gavrilinos Gavrielides Showed which manual to use to learn to program On 2/2/09 Successful connection of a point to hub network using MoteView software On 2/7/09 conducted test on fiberglass composite board with embedded transducers Tapping on composite proved to show transmission between PVDF�s was successful Established a larger network using the MTS310CA sensor motes 24

25. Gantt Chart 25

26. Q&A 26