Watermelon Ripeness Sensor

1. WatermelonRipeness Sensor Melon Inc. In Search of Perfect Melons. Jason L. Firko Allan Cohen Matt Behr Dave Bartoski

2. Watermelon Ripeness Sensor Melon Inc.“In search of perfect melons” Jason L. Firko Allan Cohen Matt Behr Dave Bartoski Customer: Ed Kee Advisor: Dr.James Glancey Mission: Develop a non-destructive method and apparatus for accurately measuring the properties of watermelons which could correlate to ripeness. Approach: Use customer wants to research and develop the most useful solution to the problem of determining the properties of watermelons which could be used in the development of non-destructive watermelon ripeness testing. Design a prototype and test it in an actual working environment.

3. Presentation Overview • Introduction • Mission, background, wants, constraints • Benchmarking • Metrics • Concept generation & selection • Concept development • Prototype • testing, budget, hours • Conclusion

4. Background Watermelon market is a large Grown on 5 Continents Grown in 90 countries Annual production 50 billion lbs./year 75% of the melons bought whole Large domestic and international market Problem with a long history - 1905 University of Georgia Study There are currently no accurate non-destructive testing methods commercially available

5. Initial Systems Benchmarking • Current Methods Of Watermelon Testing • Traditional - Thumping, stem color, skin color, other traditional methods • Destructive Testing - Sucrometer readings • Near Infrared Testing - Experimental technique of sensing sugar content • Acoustic Testing - University of Oklahoma

6. Systems Benchmarking Cont. • Related Procedures (Fruits and others) • Thumping/Resonance Tires, Fruits • Acoustic testing Acoustic emission testing • Ultrasonic testing Materials, Medical • Optoelectrics Apples • Intrusive testing Medical(syringes) • Nuclear magnetic resonance Fruits, Medical • Electronic sniffing Strawberries

7. Customers & Wants

8. 1. Accuracy 2. Portability 3. Food Quality 4. Cost 5. Durable 6. Easy to Use 7. Fast 8. Versatility 9. Maintenance 10. Service Life 1. Maximum - $3000 budget 2. Abide by all FDA regulations Food quality 3. Abide by all OSHA regulations Safety standards Top Wants and Constraints

9. Metrics/Target Values • Metrics • Provide a means of objective measurement • Eliminate ambiguity • Target Values • Derived from customer wants, functional benchmarking, continued customer dialogue • Contact regulatory agencies • Listed with related wants (ranked) • Metrics and target values have been evolving with the project throughout the year

10. Metrics & Target Values • Accuracy Target Value • Correlation coefficient 0.5 • Dimensional measurement  < 0.5in • Sound wave deviation  /max signal <.05 Portability • Weight 51 lbs. • Size (dimensions) 3’ Sides • # People - transport/operation 1 Durability • Hours of continuous operation 12 hrs. • Impact resistance 30 lb static load Ease of Use/ Speed • Level of education required Some college

11. Time to train 4 hr. • Number of steps 5 • Time/cycle 10 sec. • Time per shipment 2 hrs. • Food quality • Size of intrusion 1 mm. • Bacteria introduced 0 • Visual quality inspection rating 9 (out of 10) • Service life/Maintenance • Estimated years of service 5 yrs • Cost/cycle (parts, upkeep, etc) $.01/cycle Versatility • Additional sensor adaptable Yes • # of uses (melon types, sizes, etc.) 4 Cost • Production cost (materials) $1500

12. ACOUSTIC RESONANCE ELECTRICAL PROPERTIES ULTRASOUND NUCLEAR MAGNETIC RESONANCE (NMR) SONIC TESTING - SINGLE FREQUENCY SONIC TESTING - WHITE NOISE INFARED ENERGY IMPACT STRAIN GAUGE FLUID EXTRACTION Concept Generation

13. Concept Evaluation/ Selection Process • Is this a viable solution? • Evaluate in terms of ranked metrics • Presentation - Time Constraints • Method - Comparison with metrics(related wants) • Strong in metrics • Weak in metrics • Notes on concept • SSD and Testing results lead to selection

14. Concept Evaluation • Nuclear Magnetic Resonance • *Out of Budget - $60,000 - $1,000,000 • Sonic Testing- Single Frequency • Food quality, Speed *Need Proper Environment • Easy to use, Accuracy, Maintenance, Cost, Environment • Sonic Testing- White Noise • Food quality *Need Controlled Conditions • Speed, Cost, Accuracy, Portability, Easy to use • Infrared • Accuracy, Speed, Food quality *Auxiliary Power • Expensive, Easy to use, Portability Equiptment Needed

15. Concept Evaluation (Cont’d) • Energy Impact • Quick, Easy, Food quality, Portability, Durability • Accuracy *Not Internal • Strain Gauge • Portable, Food quality *Rind Properties • Easy to use, Speed, Accuracy • Fluid Extraction With Syringe • Accuracy, Portability, Easy to use *Intrusive • Food quality, Maintenance

16. Ultrasound • Testing - CCM • Catch 22 • High frequency - Cannot penetrate rind • Low frequency - Cannot sense density changes • Other problems - Air pockets, Seeds • Food quality, Service life, Versatility • Accuracy, Portability, Cost, Speed • Not a viable sensing mechanism

17. Electrical Properties • Resistance testing • RC modeling • Data normalized for physical parameters & sugar content • Portability, Cost, Maintenance, Service life • Accuracy, Food quality, Speed • No correlation found - not a viable sensing mechanism

18. Acoustic Resonance Testing • Based on traditional method - acoustic properties have been used to determine ripeness • Resonance traditionally indicates ripeness • Ripening of melons changes physical structure which should alter acoustic response • Accuracy, Portability, Food quality, Cost, Easy to use, Fast • Maintenance, speed

19. General Setup • Main parts • Sensory • Signal conversion • Peripheral equipment • Measurement equipment • Data Analysis/Interface • Thumper

20. Feasibility of concept • Must determine: • Repeatability and reliability • Determination of relevant variables • Required prototype components • Possible signal characteristics which may relate to ripeness • Testing of concept aids in design evolution

21. Concept Feasibility - Testing • Performed testing - 18 melons • -All melons were in ripe range (8 - 12% sugar) • Determined repeatability and reliability -Stationary repeated testing -Impact height -Background noise -Turning • Background noise - crucial for feasibility • -Tested with working environment noise • -voices, background equipment, etc. (65db)

22. Varying Height of Thumper • Repeatable at each height • See clear shift in signal amplitude • Amplitude could indicate physical properties if impact is kept constant

23. Rotation of watermelon • Indicates uniform internal structure • One possible source of error during operation is eliminated

24. Prototype Components • Developed through wants and concept testing • System Elements • Sensory: Standard microphone elements • Signal conversion: PCMCIA Card • Peripheral equipment: power source, connecting board/cable • Measurement equipment: potentiometers • Data Analysis/Interface • Laptop with Labview interface • Program components: continuous scanning, system voltage monitoring/warning, required displays/analysis

25. Prototype Evolution [i] - Experimental set up - Dr. Sun’s Lab [ii] - Initial prototype [iii] - Final testing apparatus

26. Prototype Evolution Lab Setup: - Had the basic elements - Large separate units - AC powered Initial Prototype: - Basic layout determined - Portable - DC Powered Final Prototype: - Easier to use - More durable - Even more portable - Faster - Lower maintenance

27. Final Prototype

28. Final Prototype General Electrical Layout Prototype: Physical Features Laptop Computer Microphone Battery 3.0 V Microphone • Easy adjustments • Sealed electronics • Portable Connector Potentiometer Battery 1.5V Potentiometer Battery 1.5V • Easy to inspect • Low maintenance • Durable construction

29. Prototype Display/Interface

30. Seven repeated signals Average standard deviation:  = 6.70 binary data points max signal = 150 binary data points  / max signal = 0.0447 Repeatability of Signal Acquisition

31. 616 840 6 cycles Steady State Frequency Calculation * Ten waveforms analyzed for characteristic frequency

32. Results/Correlation • Raw Data • Correlation found between dominant frequency and sugar content • Promising correlation coefficient found (R^2=.4436) • Normalization • Normalized using volume approximation as multiplier. • Significantly improves correlation coefficient (R^2=.8086)

33. Metrics with Target Values and Test Results • Accuracy Target ValueTest Result • Correlation coefficient 0.50.81 • Dimensional measurement  < 0.5in0.25in • Sound wave deviation  /max signal <.05 0.045 Portability • Weight 51 lbs.18.2 lbs • Size (dimensions) 36 in Sides17 x 17.5 x 11 in • # People - transport/operation 1 1 Durability • Hours of continuous operation 12 hrs. 4 hrs./336 hrs. • Impact resistance 30 lb static load 30 lb static load Ease of Use/ Speed • Level of education required Some college Some college

34. Time to train 4 hr. 3 hr. • Number of steps 5 6 • Time/cycle 10 sec. 12 sec. • Time per shipment 2 hrs. 2.1 hrs. Food Quality • Size of intrusion 1 mm. 0 mm. • Bacteria introduced 0 0 • Visual quality inspection rating 9 (out of 10) 10 Service Life/Maintenance • Estimated years of service 5 yrs 10 yrs • Cost/cycle (parts, upkeep, etc) $.01/cycle $.003/cycle Versatility • Additional sensor adaptable Yes Yes • # of uses (melon types, sizes, etc.) 4 4 Cost • Production cost (materials) $1500 $1080.81

35. Budget Item $Cost$ • Computer & accessories975.70 • Base & accessories 25.85 • Microphone assembly 7.54 • Thumper assembly 11.89 • Caliper assembly 41.40 • Miscellaneous 18.43 • Total 1080.81 EventHours • Engineeringdevelopmenttime1135.9 • Machine time 50.03

36. Future Improvements • Addition of filters to improve FFT analysis • Adapters for length caliper • Purchase a spare battery & power inverter • Motorized thumper • Further refine data correlation • Incorporation of ripeness correlation into program • Replace laptop with microprocessor

37. Conclusions • Our customer is satisfied with the result of the project. • The customer is encouraged by the determination of an initial correlation. • The speed of the apparatus is 20% slower then we had hoped. • The hours of continuous use for the laptop is currently lower then initially desired. • Our customer is very pleased with the portable design of the device. • We have reached the majority of our target values and are pleased with the final prototype.

38. Project Goal • Satisfied Customers!