lang
Uploaded by
18 SLIDES
335 VIEWS
180LIKES

Advanced Capacitive Rain Sensor for Automatic Wiper Control: ECE 480 Project Overview

DESCRIPTION

This presentation discusses the design and implementation of a capacitive rain sensor intended for automatic wiper control. In contrast to traditional optical sensors, our capacitive design offers higher accuracy, reduced size, and lower costs. We outline the theoretical background, detailed specifications, and a proposed design solution involving dedicated ICs for capacitance measurement and a microcontroller for data processing. Our design ensures compatibility with existing systems, targeting an overall cost of under $12. The project showcases innovation in enhancing vehicle safety and functionality.

1 / 18

Download Presentation

Advanced Capacitive Rain Sensor for Automatic Wiper Control: ECE 480 Project Overview

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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. Agenda • Introduction • Background • Design Specifications • Conceptual Design • Proposed Design Solution • Hardware Specifications • Reflection

  3. Introduction GPS Ipod/MP3 In-Dash DVD Player Safety Satellite Radio

  4. BackgroundOptical Rain Sensors • Transmits/Receives IR Beams • Expensive • Inaccurate (False Readings) • Uneven Sensing Area

  5. BackgroundWhy Capacitive? • Higher Accuracy – Less False Positives • Smaller Size – Sleek Design • Cheaper • Fewer Components – Less Complex

  6. BackgroundBasics of Capacitive Sensors • Three Main Types: • Displacement • Accelerometer • Pressure • Capacitance • Fringe Fields • Dielectric differences

  7. Design Specifications • COMPATIBILITY • Fit in existing housing (1250 mm2) • Mount via adhesive • COST • Cheaper than optical sensor • Overall cost < $12 • FUNCTIONALITY • Sense water through windshield • Communicate with microcontroller • Control Wiper System • ACCURACY • Differentiate between various objects • Differentiate varying rain levels

  8. Conceptual DesignSensor Traces • Not Your Typical Capacitor! • Sensing Area – Copper Traces • Designed for Base Capacitance ≈ 5 pF • Creates E-field When AC Voltage Applied • Objects Interfere with E-field – Change Cin • Design Parameters: Size, Spacing, Pattern • Dielectric Insulators are Vital!

  9. Conceptual DesignCapacitance Monitoring Circuitry • Need Circuitry to Monitor the Capacitance Value of the Sensor Traces • Possible Design: RC Multi-vibrator - Change in C = Change in Time Constant • Better Alternative: Dedicated IC’s – Capacitance to Digital Conversion • Interface to Microcontroller for Software Processing

  10. Conceptual DesignMicrocontroller / Processor • Inputs Capacitance Data from C-D IC • Sensor Response to Rain Can Be Characterized • Software Algorithms To Discriminate Rain from Others • Varying Wiper Speed In Response to Amount of Rain • Prototype – Microcontroller • Production – Body Control Module

  11. Proposed Design SolutionCapacitance-to-Digital Converter • Use Analog Devices AD7746 • Measures 24-bit capacitance • Accurate to the femto-Farad • Built in temp and humidity sensor for auto-compensation • AD7151 and AD7747 models can also be used

  12. Proposed Design SolutionDifferential Sensor Trace Design • Three Separate Traces • Source Excitation Voltage Applied To Center Trace • Two Differentially Connected Traces • Test Results to Determine Best Design (spacing, patterns, etc)

  13. Proposed Design SolutionPIC18F4520 Microcontroller • Why we chose the PIC: • Variety of I/O Ports • Easy to use interface • C++ programming • Free! • Can compare voltages

  14. Proposed Design SolutionPower Supply and Requirements • Prototype will use batteries (9V Batteries) • Production Design will use car battery • PIC needs steady 5V • AD7746 (C-D) needs steady 5.6V • Buck Converter Circuit

  15. Proposed Design SolutionPCB Layout • Final design has two parts: • Flex PCB: • Sensor Traces • Mounts via 3M Adhesive • Standard 2-layer FR4 PCB: • C-D Converter • Microcontroller

  16. Hardware Specifications • Overall Design uses 3 layers • Flex Layer – Capacitive Sensor • C-D Converter (AD7746) • Buck Converter Circuit • Microcontroller (PIC18F4520) • Wiper Switch

  17. Budget

  18. Reflection • Background • Design Specifications • Conceptual Design • Proposed Design Solution • Hardware Specifications • Questions?

More Related