Soil Testing Data Logger Final Presentation April 21, 2011.
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Transcript of Soil Testing Data Logger Final Presentation April 21, 2011.
Soil Testing Data LoggerFinal Presentation
April 21, 2011
Team Members
Cody Griffin
Op Amp CircuitryVDIP CommunicationHardware TestingNormal Mode Design
Electrical Engineering
Daniel Herrington
Software Design LeadVDIP CommunicationSoftware TestingWebsite Design
Electrical Engineering
Ashley Stockbridge
RTCC Software DesignSetup Mode DesignNormal Mode DesignSoftware Testing
Electrical Engineering
Matt Weissinger
PCB DesignOp Amp CircuitryHardware TestingComponent Research
Electrical Engineering
Outline
• Background• Problem• Solution• Constraints
– Technical– Practical
• Refinements• Packaging• Production• System Testing
Background: Soil Redox Potential
• Electrical property of soil that correlates to the specific chemicals present in the ground
• Research topic of Dr. Kroger with the Forest and Wildlife Research Center at MSU
Problem: Chemical Runoff
• Caused by fertilizers and pesticides used on farmlands
• Can be controlled using a detailed historical set of soil redox data
• No efficient method for collecting soil redox measurements
Problem: Chemical Runoff
[1]
Solution: Soil Testing Data Logger
• Reduces the time associated with taking soil redox potential measurements in the field
• Periodically takes soil redox potential and associated temperature measurements
• Stores all measurements in a removable USB storage device
Technical Constraints
Constraint Description
Inputs The device must support four soil probe inputs and five temperature inputs.
Soil Redox Potential Input Range
The device must be able to measure potentials that range from -600mV to +600mV with an accuracy of ±10mV.
Temperature Indicator Input Range
The device must be able to measure temperatures that range from -40°C to 125°C with an accuracy of ±1°C.
Data Storage The device must store soil redox potential and temperature data on a removable USB storage device.
Sample Rate The device must store sample data every 20 minutes.
Practical Constraints
Type Constraint Description
Manufacturability Size The size of the circuit board must be no larger than 3.1” x 3.9”.
Environmental Operating Conditions The device must be able to operate in extreme weather conditions.
Manufacturability
• No larger than 3.1” x 3.9”• Easily accessible for routine maintenance• Organized for easy assembly
Environmental
Cleveland, MS
[2]
Refinements
• PCB– Added third RJ45 connection– Added programming header– Minor silkscreen changes
• Software– Delayed start-up– Time-stamped filename– Refined setup menu
PCB Refinements
• Allows for grouping of soil/temp probe pairs• Lowers difficulty of manufacturing soil/temp probes
Software Refinements
• Delayed start-up– Useful to synchronize multiple data loggers– Easy initialization in setup menu
• Time-stamped filename– Filename is start date of sample period– Creates multiple files if more than one sample is
created in the same day
Packaging
• PCB is final packaging for data logger
• Soil / Temp probes are waterproofed using:– RJ45 cables– Heat shrink– Water tight sealant
Temperature Testing Data
Soil Redox Probe Testing Data
Production
Parts $61
PCB $24
Assembly $104
Total $189
[4]
[5]
[3]
References
[1] “The Gulf of Mexico Dead Zone,” Microbial Life: Educational Resources. 2011.http://serc.carleton.edu/microbelife/topics/deadzone/
[2] “Season Weather Averages for Mid Delta Regional,” Weather Underground. 2010. http://www.wunderground.com/NORMS/DisplayNORMS.asp?AirportCode=KGLH&SafeCityName=Cleveland&StateCode=MS&Units=none&IATA=GLH
[3] “Digikey,” Digikey. 2011http://digikey.com
[4] “PCBEX – Product Prices,” PCBEX. 2011.http://pcbex.com/Product/#2
[5] “Online Quote,” 2011.http://aapcb.com/online_quote.asp
Questions?Questions?