Moisture Controlled Irrigation System Team Members: ECE - Aaron Beekman, Adrian Fletcher, and Derek Thomas CECS – Jacob Schreiver

Background Info Swan Florist and Gift Shop is a family run business located in Erlanger, Ky. Operate multiple greenhouses Several greenhouses are located at a remote location Maintained by employees 2-3 times per week Uses a timer system to water plants once a day

Greenhouse Layout

Existing Irrigation System

Project Requirements Irrigate plants based on soil moisture content Use existing sprinkler valves Require minimal operator intervention Perform data logging of moisture content, greenhouse temperature, when and how long plants were watered Provide a Graphical User Interface that will allow the user to change moisture thresholds to maintain proper watering for plants At least 10 different threshold levels Restart after a power outage without reprogramming

System Diagram

Moisture Sensor Requirements Designed for potted plants Need at least 8 Input voltage of 5 VDC Cost Effective

Temperature Sensors 2 required Either commercial-off-shelf or self-designed Cost effective choice Located in two neutral locations chosen by sponsor. Input voltage of 5 volts Linear return within expected greenhouse temperatures. About 40 – 110 degrees Fahrenheit

Sprinkler Valves Need to interface with 8 sprinkler valves Input Voltage 26.8 VAC 8 Watts per valve No more than 2 valves on at one time.

Power Converter Use existing 26.8 VAC Transformer Converts 120VAC to 26.8VAC VAC Powers Sprinkler Valve Solenoids Provides power to AC/DC Rectifier Custom AC/DC Rectifier to power control board

Control Board Hardware Requirements Programmable microcontroller Minimum of 10 analog input channels To interface with all sensors Minimum of 10 digital I/O 8 relays control 2 communication 8 relays either on-board or daughter card Provides 26.8VAC to the sprinkler valves Integrated RS232 interface Capable of powering sensors

Control Board Software Requirements Send/Receive Serial data Execute commands received from Display/Data Management System Close and Open relays Acquire and transmit A/D values from each sensor input

Display/Data Management System Serial Communication with control board Watering Scheduler Waters plants at schedule time Water plants according to moisture content Data Logging Log sensor and watering information Graphical User Interface Allows user to see visual representations of sensor readouts Control schedule times for watering Control threshold levels View graphical representation of data Export data log via a comma separated values (.csv) file

Detailed Design

Moisture Sensors

Volumetric Water Content Vegetronix VH400 Designed for potted plants Independent of volume Input voltage of 5 VDC at.7mA Output impedance: 100kΩ Returns 0-3 VDC

Temperature Sensors

Temperature Sensor Thermistor Design 5 VDC input to temperature sensor 0-5 VDC output Approximately Linear Voltage return of VDC in typical greenhouse ranges

Voltage Buffer Daughter Card 3 Quad Op-Amps configured a voltage buffers 2 10-pin IDC connectors 2 10-pin IDC headers

Power Converter

Rectifier Circuit Uses 26.8 VAC from existing transformer Converts 26.8 VAC to 20 VDC for control board Control Board requires 16 to 28 VDC Optional 5 VDC output

Connections and Wire Management

Control Board

MikroElectronika PICPLC8A Control Board Utilizes a PIC18F4520 microprocessor Provides up to 13 A/D conversion input channels Meets requirement of 10 Provides up to 32 digital I/O pins Meets requirement of 10 8 on-board relays Meets requirement of 8 On-board RS-232 interface Meets communication requirement

Control Board Software Diagram

Control Board Software Read and transmit A/D values from sensors Receive and execute relay control commands

Display/Data Management System (DDMS)

Display/Data Management Software Java Program will control irrigation Provide Graphical User Interface for system control Set Moisture Thresholds Set Watering Times View Sensor Output Provide Data Logging Utility Log sensor values every four hours Log when plants were watered and for how long Provide a Scheduler for watering plants Communicate via RS-232 with Control Board Uses java RXTX package

DDMS Software Block Diagram

Graphical User Interface

Data Visualization

Testing Overview Code Testing Hardware Simulation Communications Testing Analog to Digital Conversion Testing Moisture Sensor Testing Temperature Sensor Testing

Code Testing JUnit Java Unit testing package Runs in Netbeans Provides Code Coverage results as well as test result validation Tests for both Java Application and Control Board

Hardware Simulator

Communications Testing Use JUnit and Netbeans Send valid data to Control Board Verify good data acknowledgement packet Send invalid data to Control Board Verify bad data acknowledgement packet Send packet requesting multiple relays on

Analog-to-Digital Converter Testing

A/D Testing From the graph on the previous slide, we found out that we needed to power the sensors from the control board. This is due to the control board having an on-board bridge rectifier for power input that creates a ground difference. Powering the sensors from the board corrects the A/D results shown in the previous slide

Corrected A/D Testing

Moisture Sensor Testing

Moisture Sensor voltage readings were correct when measured using a digital multi-meter Moisture Sensors did not output correctly when connected to the A/D converter on the control board Caused by impedance mismatch 100KΩ moisture sensor 2.5KΩ max A/D Solution Add voltage buffer for each sensor input prior to the control board to reduce output impedance A developed daughter card with each voltage buffer circuit will added to the control board

Temperature Sensor Testing Confirmed temperature sensor circuit varied voltage output with varying temperature Plan to use an infrared heat gun to calibrate the sensor Sensor Calibration Dialog will be used to adjust calibration coefficients so the measured temperature values correlate to the heat gun read out

Recommendations Internet connectivity alerts/text alerts Remote access Software Updates/Patches Automated Error Reporting UPS battery backup Allow for safe shutdown of system Incorporate more sensors per bench Expansion daughter card to allow for multiplexing analog inputs Completely moisture controlled watering option

Questions? Moisture Controlled Irrigation System

Moisture Sensor Testing

Software Development Environment Netbeans IDE Java Development for the frontend Application GUI and Form Builder Code Completion Software Debugger Unit Testing Support for Multiple Programming Languages

Temperature Calibration