ECE 445 Smart Window Responding System Group #8 TA: Zipeng Wang Xuanzhen Cao Jiaxi Nie Zhichun Wan

Introduction Open Window Dust Storm Rain Temperature Rise/Drop

Objectives 1. Automatically close the window after detecting raindrops; 2. Automatically close the window after detecting an air quality drop; 3. Automatically close the window after detecting a significant temperature rise or drop crossing a preset threshold 4. Instantly stop the window from closing after detecting presence of human limbs or pets resting on rails.

Block Diagram

Block Diagram

Power Supply Module Power Supply Overview Functions: 12V supply to actuator 5V supply to sensors and microcontroller Considerations: 5V supply must be stable Implementations: Connect 12V battery directly to Motor’s driver Use voltage regulator to obtain 5V supply

Power Supply Batteries Battery Choice 8 AA batteries in series for 12V voltage source AA battery: 1.5V each, 2875mAh capacity

Power Supply Voltage Regulator Design: Use 3-Terminal Voltage Regulator LM317   Capacitor: Ripple rejection Diode: Chip Protection

Power Supply

Power Supply Verifications Battery: 12.8V with new battery 11.7V after 5h operation Voltage regulator: 5.07V stable

Sensing Module

Rain Sensor Input: 5V DC Output: Analog output to microcontroller No rain: output high Rain: output low -25% of sensing board covered by rain Sensor Driver: implemented on PCB

Rain Sensor Input: 5V DC Output: Analog output to microcontroller No rain: output high Rain: output low -25% of sensing board covered by rain Sensor Driver: implemented on PCB

Temperature Sensor Input: 5V DC Output: Analog output to microcontroller Analog Output: Linearly proportional to temperature Range: 20~30°C Error: <1°C

Temperature Sensor Input: 5V DC Output: Analog output to microcontroller Analog Output: Linearly proportional to temperature

Temperature Sensor Input: 5V DC Output: Analog output to microcontroller Analog Output: Linearly proportional to temperature Range: 20~30°C Error: <1°C

Dust Sensor Input: 5V DC Supply 5V DC LED Supply Output: Analog output to microcontroller Detection Accuracy: >80% Delay: <5s

Dust Sensor Light Emitter: LED →Light Pulse Light Detector: Photodiode

Dust Sensor Input: 5V DC Supply 5V DC LED Supply Output: Analog output to microcontroller Detection Accuracy: >80% Delay: <5s Baseline

IR Sensor Input: 5V DC Output: Digital output to microcontroller Detect infrared: - No detection: output low - Object detected: output high Accuracy: >95% Response Time: <1s Detection Range: <30sm

IR Sensor

IR Sensor Input: 5V DC Output: Digital output to microcontroller Detect infrared: - No detection: output low - Object detected: output high Accuracy: >95% Response Time: <1s Detection Range: <30sm

IR Sensor Input: 5V DC Output: Digital output to microcontroller Detect infrared: - No detection: output low - Object detected: output high Delay: 3s

IR Sensor Input: 5V DC Output: Digital output to microcontroller Detect infrared: - No detection: output low - Object detected: output high Response Time: 1.2us

Microcontroller Overview Functions: Collect input signals from sensors Output control signals to the H-bridge Decision making for system behavior Implementations: ATmega328P chip Programmed with Arduino bootloader

Microcontroller

Microcontroller

Check safety module reading Microcontroller Initalize Poll sensors data Check safety module reading Make Decision Send Signals to Motor

Microcontroller Design Threshold selection: Temperature — up_limit: 28°C, down_limit: 20°C Dust sensor — 0.255 mg/m3. Rain sensor — 900 Buffered thresholds to reduce glitches A/D conversion in Arduino: Varduino = V/5.1 * 1024 Clock: external 16 MHz oscillator LED blinking: timer interrupt signals (2Hz)

Microcontroller Verification(average): Input signals accuracy <= 10mV Output signals accuracy <= 20mV Response time(average): IR sensor ~ 18ms Temperature sensor ~ 25ms Rain sensor ~ 30ms Dust sensor ~ 30ms

Actuator Module Overview Functions: Drive the actuator based on control signals Implementations: Linear Actuator Driver Circuit (H-Bridge)

Actuator Module Driver (H-Bridge) Considerations: 2 control signals Design: Control signal controls Q5,Q6 Q5 controls Q1,Q3 Q6 controls Q2,Q4

Actuator Module

Actuator Module Driver (H-Bridge) Verification: Open Close Motor (V) 1 1 +11.991 -11.992

Actuator Module Linear actuator Specs: Operating Voltage: 9 ~ 16V Max extension length: 30cm Stroke Speed: 1cm/s Load Capacity: 750N (170LB) Usage: Mounting Brackets

Power Consumption    

Future Work

Future Work Power Supply Replace battery 120V AC input with AC/DC Converter

Future Work Wireless communication between modules

Future Work Sensor networks IR sensor Temperature sensor

Future Work User Interface Graphical User Interface(GUI) SD Card

Future Work Environment Adapting Machine learning Alternative microcontroller

Conclusion All functionalities realized 6 PCBs soldered and tested LED matrix added Future work

Acknowledgement Special thanks go to our TA: Bird

Q&A