ECE 480 – Team 6

1. Capacitive Rain Sensor for Automatic Wiper Control ECE 480 – Team 6 In Order of Presentation: Ishaan Sandhu Danny Kang Arslan Qaiser Eric Otte Anuar Tazabekov

2. Outline • Introduction • Design Requirements • Proposed Design Solution • Testing Results • Budget • Demonstration • Conclusions

3. Introduction Automotive Safety and Convenience Automatic Headlights Hands-Free Calling Automatic Braking Automatic Windshield Wipers Currently Optical (Expensive, Inaccurate) DT6 Proposes Using a Capacitive Based Sensor

4. Capacitive Sensor Basics

5. Design Requirements • Functionality • Detect rain through 6 mm of glass • Output control signals to wipers • Accuracy • Differentiate multiple levels of rain • Ignore false stimuli on windshield, i.e. hands and dirt • Compatibility • Fit in existing housing area (1250 mm2) • Mount via adhesive to windshield • Cost • Production cost < $16 per unit

6. System Block Diagram

7. Design Flowchart Control Unit

8. Sensor Traces COMSOL 3D Modeling Software Visual User Interface Calculates the base capacitance Can model dielectrics Top layer Bottom Layer Simulates electric field lines Sensitivity

9. Capacitance-to-Digital Converter Analog Devices AD7745 Industry-leading accuracy down to 4 fF change in capacitance Interfaces with sensor traces to monitor capacitance (+/- 4 pF) Converts changing capacitance to 24-bit digital output signal Output routed to PIC using the I2C communication system Make text larger

10. Microcontroller Microchip PIC16F1826 8-bit microcontroller, programmable in C code Initializes and configures AD7745 for operation Streams data from AD7745 and compares to known data ranges Data falling in range will activate appropriate wiper control signals Make text larger

11. Budget

12. Capacitive vs. Optical

13. Software

14. Demonstration

15. Conclusions Successful completion of the project Exceeds all design requirements Higher accuracy Larger sensing area Smaller enclosure Significant savings

16. Q & A

17. Thank You