Mid Semester Presentation DraftFebruary 17, 2011

Team MembersDuties:

Real Time Clock

Website 

Kevin Wellman

Electrical Engineering

Electrical Engineering

Electrical Engineering

Electrical Engineering

Reginald Lott

Adam Teague

Matthew Adkins

Duties:

Power Circuit

PCB Design 

Duties:

User Interface

MicroprocessorProgramming 

Duties:

Sensors

PCB Design 

Dr. Winton

Faculty Advisor

Overview:ProblemSolutionSystem OverviewConstraints

TechnicalPractical

ApproachProgress

ProblemCurrent residential sprinkler systems are inadequate

in the following areas:EfficiencyEase of useCost

SolutionWater Conserving Sprinkler Control

Periodically monitors moisture content and temperature

Operates on user-defined scheduleRequires no external devices for modifying settingsCosts less than $150

System Overview

Microcontroller

Moisture Sensor

Temperature Sensor

Power Supply

Power Output

Real Time Clock

Technical Constraints:Name  

Description

Display The WCSC display must provide relevant information and options to the user, and it must be readable in well or dimly lit environments.

Voltage The WCSC must operate from a standard 120V wall outlet.

Outputs The WCSC must be able to output 24 V AC at 0.6A .

Technical Constraints (cont.):

Name  

Description

Temperature Sensor Range

The WCSC must sense temperatures from 15 to 50 degrees Fahrenheit.

Moisture Sensor Range

The WCSC must be able to sense the volumetric water content of the soil from 20 to 50 percent.

Type Constraint Description

Environmental Durability The device must be able to operate in harsh conditions.

Usability Customer Convenience

The device must be easy to use and change watering schedule.

Environmental

•Sensors must withstand a variety of weather elements

• Heat• Cold• Water Resistant

•Control unit encasement durability• Must be rugged enough to withstand incidental impact

Usability•The unit must be simple to configure and operate.

• Water scheduling • Time changes• Display and Button Interface

Moisture ProbeModel Power

Supply Output Price Component

Chosen

VG400 3.3-20 VDC 0-3 VDC $29.95

Hydra Probe II 9-20 VDC RS485 $395

[1][2]

Power Control Model Trigger

Voltage Contact Trigger

Current

Price Component Chosen

TRIAC 1.5 V 50mA $0.78

Relay 3.3 V 60mA $19.34

[3][4]

PowerModel Ratio Power

Rating Price Component

Chosen

Plug in Transformer

120/24VAC 20VA $16.18

On board Transformer

120/24VAC 20VA $9.10

[5][6]

TimelineJanuary February March April

Research

OrderingParts

Design

Constructing and test Prototype

Working Prototype

Progress

Progress

Pic uC

ProgressRTC

Progress

Temp

ProgressOpto-Coupler

TRIAC

Simulated24v AC Load

References:[1] “VG400 Moisture Probe” [Online] Available: http://www.vegetronix.com/Products/VG400/.

[2] “Hydra Probe II.” [Online]. Available: http://www.stevenswater.com/catalog/stevensProduct.aspx?SKU=%2793640%27

[3] “Triac" [Online] Available: http://search.digikey.com/scripts/DkSearch/dksus.dll?vendor=0&keywords=568-3687+ND%09%09

[4] “Relay.” [Online] Available: http://parts.digikey.com/1/parts/1791165-relay-reed-hi-rf-bga-3-3v-spst-b10-03b.html

[5] “Plug in Transformer." [Online] Available: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T1009-ND.

[6] “On Board Transformer.” [Online] Available http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go_button&KeyWords=14A-20-24B28

Any Questions?