Mid Semester Presentation Draft February 17, 2011

Team Members Duties: Real Time Clock Website Kevin Wellman Electrical Engineering Reginald Lott Adam Teague Matthew Adkins Duties: Power Circuit PCB Design Duties: User Interface Microprocessor Programming Duties: Sensors PCB Design Dr. Winton Faculty Advisor

Overview: Problem Solution System Overview Constraints Technical Practical Approach Progress

Problem Current residential sprinkler systems are inadequate in the following areas: Efficiency Ease of use Cost

Solution Water Conserving Sprinkler Control Periodically monitors moisture content and temperature Operates on user-defined schedule Requires no external devices for modifying settings Costs 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.

Practical Constraints TypeConstraintDescription EnvironmentalDurabilityThe device must be able to operate in harsh conditions. UsabilityCustomer 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 Probe ModelPower Supply OutputPriceComponent Chosen VG VDC0-3 VDC$29.95 Hydra Probe II9-20 VDCRS485$395 [1][2]

Power Control ModelTrigger Voltage Contact Trigger Current PriceComponent Chosen TRIAC1.5 V50mA$0.78 Relay3.3 V 60mA $19.34 [3][4]

Power ModelRatioPower Rating PriceComponent Chosen Plug in Transformer 120/24VAC20VA$16.18 On board Transformer 120/24VAC 20VA $9.10 [5][6]

Timeline JanuaryFebruaryMarchApril Research Ordering Parts Design Constructing and test Prototype Working Prototype

Progress

Pic uC

Progress RTC

Progress Temp

Progress Opto-Coupler TRIAC

Simulated 24v AC Load

References: [1] “VG400 Moisture Probe” [Online] Available: [2] “Hydra Probe II.” [Online]. Available: [3] “Triac" [Online] Available: ND%09%09http://search.digikey.com/scripts/DkSearch/dksus.dll?vendor=0&keywords= ND%09%09 [4] “Relay.” [Online] Available: [5] “Plug in Transformer." [Online] Available: ND. ND. [6] “On Board Transformer.” [Online] Available ords=14A-20-24B28 ords=14A-20-24B28

Any Questions?