1. ENG4000 Monitoring Capacitance Changes over Various Materials and Fluids Aysar Khalid, Hassan Chehaitli, Mohammad Aryanpour Group 5 Course Director & Advisor: Prof. E. Ghafar-Zadeh Mentor: Giancarlo Ayala-Charca, Mourad Amara

2. Motivation Calibrating and understanding planar capacitors Detecting solid dry/wet material properties using planar capacitive sensors Current sensing technology is limited in accuracy Applications for pressure measurement, humdity sensing, impurity detection (Lubepoint et. al, 2013)

3. Background Capacitance sensors detect a change in capacitance when something or someone approaches or touches the sensor. Current techniques (ESP) unable to work on low or high resistivity gases Different particles require different techniques (Analog Devices et. al, 2006) Particle Particle Size (microns) Dust Mites100 - 300 Starches3 - 100 Asbestos0.7 - 90 Anthrax1 - 5

4. Methodology ● Planar capacitor is connected and produces Cx ● Cx occurs when excitation signal (square wave) with f= 90.9 Hz ● EVB then takes Cx and converts to digital signal using modulator/filter/etc. ● Need to ensure minimal RF/EM interference on sensor (Analog Devices et. al, 2006)

5. Progress Results To Date

8. #SampleAmount (3/10cc) Capacitance (fF) CAPDAC (hex / fF) Offset Capacitance (fF) 1Alcohol1 unit398442 / 8000.766 69.879 2Alcohol1 unit399443 / 8000.898 -30.2331 3Ginger Beer1 unit3894.13443 / 8000.898 -9.472 4Ginger Beer1 unit3623.64143 / 8000.898 -9.102 5Water1 unit3920.9243 / 8000.898 -2.317 6Water1 unit3900.9943 / 8000.898 -2.338

10. Discussion From the last presentation Sensor shielding and grounding Developed and used aluminum die-cast casing for shielding Various fluids and better instrumentation Calibration and stability

11. Conclusion ; Next Step Make shielding more secure Test more fluids/materials and samples for more tests Connect sensor with LabView setup for data logging Noise from Laptop/measuring instrument

12. Acknowledgements Thanks to All the People and Organizations who technically or financially supported your project