Introduction

Due to the unpredictable nature of Illinois’s weather, many have returned to their homes to discover expensive electronics and belongings ruined by rain incoming from a nearby window that was never closed. Our project aims to use an analog rain sensor to detect inclement weather and automatically close a window with a DC motor, preventing rain from entering the room.

As is commonly known, exposing bare electronics to water creates shorts in the circuitry, burning out expensive circuits and rendering the entire device inoperable. We believe that by monitoring the current (SOURCE HERE, YO) in a rain sensor, it is possible to detect the amount of rain on a conductive surface. By then comparing the current of this circuit to a preset threshold in a comparator circuit (Texas Instruments), a digital signal can be sent when the current from the rain sensor surpasses the threshold current.

Design Details

As the surface of the rain sensor begins to collect rain, the resistance decreases, causing a shift in analog current supplied to a comparator circuit. If the current surpasses a threshold, determined by comparing the current of the rain sensor with the current of a potentiometer, the comparator will send a digital signal to a TI MSP 430 microcontroller. Once this signal is received, the MS 430 simultaneously send a signal to a DC motor to turn a gear system, closing the window. Once a reed switch detects that the window is closed, a signal will be sent, stopping the motor. Meanwhile, a digital signal will be sent to an ESP 8266 WiFI Module, which will send an Android Push Notification to the user’s phone, alerting him or her that their window was closed. This system is supplied current via a 5V DC Power Supply.

Pecht, M. 2009. Prognostics and Health Management of Electronics. Encyclopedia of Structural Health Monitoring. .
LMx93-N, LM2903-N Low-Power, Low-Offset Voltage, Dual Comparators, Texas Instruments

Final Report