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

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.

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

Background lWatermelon market is a large lGrown on 5 Continents lGrown in 90 countries lAnnual production 50 billion lbs./year l75% of the melons bought whole lLarge domestic and international market lProblem with a long history University of Georgia Study lThere are currently no accurate non- destructive testing methods commercially available

Initial Systems Benchmarking l 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

Systems Benchmarking Cont. lRelated Procedures (Fruits and others)  Thumping/ResonanceTires, Fruits  Acoustic testing Acoustic emission testing  Ultrasonic testing Materials, Medical  Optoelectrics Apples  Intrusive testing Medical(syringes)  Nuclear magnetic resonance Fruits, Medical  Electronic sniffingStrawberries

Customers & Wants

Top Wants and Constraints 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 l Food quality 3. Abide by all OSHA regulations l Safety standards

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

Metrics & Target Values Accuracy Target Value lCorrelation coefficient 0.5 lDimensional measurement  < 0.5in lSound wave deviation  /max signal <.05 Portability lWeight 51 lbs. lSize (dimensions) 3’ Sides l# People - transport/operation 1 Durability lHours of continuous operation 12 hrs. lImpact resistance 30 lb static load Ease of Use / Speed lLevel of education required Some college

lTime to train 4 hr. lNumber of steps 5 lTime/cycle 10 sec. lTime per shipment 2 hrs. Food quality lSize of intrusion 1 mm. lBacteria introduced 0 lVisual quality inspection rating 9 (out of 10) Service life/Maintenance lEstimated years of service 5 yrs lCost/cycle (parts, upkeep, etc) $.01/cycle Versatility lAdditional sensor adaptable Yes l# of uses (melon types, sizes, etc.) 4 Cost lProduction cost (materials) $1500

Concept Generation lACOUSTIC RESONANCE lELECTRICAL PROPERTIES lULTRASOUND lNUCLEAR MAGNETIC RESONANCE (NMR) lSONIC TESTING - SINGLE FREQUENCY lSONIC TESTING - WHITE NOISE lINFARED lENERGY IMPACT lSTRAIN GAUGE lFLUID EXTRACTION

Concept Evaluation/ Selection Process lIs this a viable solution? lEvaluate in terms of ranked metrics lPresentation - Time Constraints l Method - Comparison with metrics(related wants) ö Strong in metrics ÷ Weak in metrics S Notes on concept lSSD and Testing results lead to selection

Concept Evaluation 8Nuclear Magnetic Resonance *Out of Budget - $60,000 - $1,000,000 8Sonic Testing- Single Frequency ùFood quality, Speed * Need Proper Environment ÷Easy to use, Accuracy, Maintenance, Cost, Environment 8Sonic Testing- White Noise ùFood quality *Need Controlled Conditions ÷Speed, Cost, Accuracy, Portability, Easy to use 8Infrared öAccuracy, Speed, Food quality *Auxiliary Power ÷Expensive, Easy to use, Portability Equiptment Needed

Concept Evaluation (Cont’d) 8Energy Impact öQuick, Easy, Food quality, Portability, Durability ÷Accuracy *Not Internal 8Strain Gauge öPortable, Food quality *Rind Properties ÷Easy to use, Speed, Accuracy 8Fluid Extraction With Syringe ùAccuracy, Portability, Easy to use *Intrusive ÷Food quality, Maintenance

Ultrasound lTesting - CCM lCatch 22 l High frequency - Cannot penetrate rind l Low frequency - Cannot sense density changes lOther problems - Air pockets, Seeds öFood quality, Service life, Versatility ÷Accuracy, Portability, Cost, Speed lNot a viable sensing mechanism

Electrical Properties lResistance testing lRC modeling lData normalized for physical parameters & sugar content ùPortability, Cost, Maintenance, Service life ÷Accuracy, Food quality, Speed lNo correlation found - not a viable sensing mechanism

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

General Setup l Main parts l Sensory l Signal conversion l Peripheral equipment l Measurement equipment l Data Analysis/Interface l Thumper

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

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) Concept Feasibility - Testing

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

Rotation of watermelon –Indicates uniform internal structure –One possible source of error during operation is eliminated

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

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

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

Final Prototype

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

Prototype Display/Interface

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

Steady State Frequency Calculation 6 cycles * Ten waveforms analyzed for characteristic frequency

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)

Metrics with Target Values and Test Results Accuracy Target Value Test Result lCorrelation coefficient lDimensional measurement  < 0.5in 0.25in lSound wave deviation  /max signal < Portability lWeight 51 lbs lbs lSize (dimensions) 36 in Sides 17 x 17.5 x 11 in l# People - transport/operation 1 1 Durability lHours of continuous operation 12 hrs. 4 hrs./336 hrs. lImpact resistance 30 lb static load 30 lb static load Ease of Use / Speed lLevel of education required Some college Some college

lTime to train 4 hr. 3 hr. lNumber of steps 5 6 lTime/cycle 10 sec. 12 sec. lTime per shipment 2 hrs. 2.1 hrs. Food Quality lSize of intrusion 1 mm. 0 mm. lBacteria introduced 0 0 lVisual quality inspection rating 9 (out of 10)10 Service Life/Maintenance lEstimated years of service 5 yrs 10 yrs lCost/cycle (parts, upkeep, etc)$.01/cycle $.003/cycle Versatility lAdditional sensor adaptable YesYes l# of uses (melon types, sizes, etc.) 4 4 Cost lProduction cost (materials) $1500 $

Budget Item $Cost$ $ Computer & accessories $ Base & accessories $ Microphone assembly 7.54 $ Thumper assembly $ Caliper assembly $ Miscellaneous $ Total EventHours Engineering development time Machine time 50.03

Future Improvements 4Addition of filters to improve FFT analysis 4Adapters for length caliper 4Purchase a spare battery & power inverter 4Motorized thumper 4Further refine data correlation 4Incorporation of ripeness correlation into program 4Replace laptop with microprocessor

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.

Project Goal Satisfied Customers!