1. Soil Testing Data Logger Final Presentation April 21, 2011

2. Team Members Cody Griffin Op Amp Circuitry VDIP Communication Hardware Testing Normal Mode Design Electrical Engineering Daniel Herrington Software Design Lead VDIP Communication Software Testing Website Design Electrical Engineering Ashley Stockbridge RTCC Software Design Setup Mode Design Normal Mode Design Software Testing Electrical Engineering Matt Weissinger PCB Design Op Amp Circuitry Hardware Testing Component Research Electrical Engineering

3. Outline Background Problem Solution Constraints – Technical – Practical Refinements Packaging Production System Testing

4. 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

5. 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

6. Problem: Chemical Runoff [1]

7. 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

8. Technical Constraints ConstraintDescription InputsThe 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 StorageThe device must store soil redox potential and temperature data on a removable USB storage device. Sample RateThe device must store sample data every 20 minutes.

9. Practical Constraints TypeConstraintDescription ManufacturabilitySizeThe size of the circuit board must be no larger than 3.1” x 3.9”. EnvironmentalOperating ConditionsThe device must be able to operate in extreme weather conditions.

10. Manufacturability No larger than 3.1” x 3.9” Easily accessible for routine maintenance Organized for easy assembly

11. Environmental Cleveland, MS [2]

12. Refinements PCB – Added third RJ45 connection – Added programming header – Minor silkscreen changes Software – Delayed start-up – Time-stamped filename – Refined setup menu

13. PCB Refinements Allows for grouping of soil/temp probe pairs Lowers difficulty of manufacturing soil/temp probes

14. 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

15. Packaging PCB is final packaging for data logger Soil / Temp probes are waterproofed using: – RJ45 cables – Heat shrink – Water tight sealant

16. Temperature Testing Data

17. Soil Redox Probe Testing Data

18. Production Parts$61 PCB$24 Assembly$104 Total$189 [4] [5] [3]

19. 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=Cle veland&StateCode=MS&Units=none&IATA=GLH http://www.wunderground.com/NORMS/DisplayNORMS.asp?AirportCode=KGLH&SafeCityName=Cle veland&StateCode=MS&Units=none&IATA=GLH [3] “Digikey,” Digikey. 2011 http://digikey.com [4] “PCBEX – Product Prices,” PCBEX. 2011. http://pcbex.com/Product/#2 [5] “Online Quote,” 2011. http://aapcb.com/online_quote.asp

20. Questions?