Calvin CollegeEngineering Senior Design

Team 10May 3, 2008

OutlineIntroduction

MFC

Power Regulation

System Monitoring

Feed/Waste System

Jared Huffman

Brianna BultemaAchyut Shrestha

Chris Michaels

Team 10: Members

Why Biobattery?

Problems of Conventional Batteries

“Hard to Do”

Interdisciplinary Talents

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Design GoalsUSB Power OutputRefillable Food Supply with Alert

Semi-ContinuousSystem Monitoring

User friendlyIndicates Failure Mode

Improved Power/Volume RatioAnode Cube

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Project DivisionFour Main Parts of

Our Biobattery ProjectMicrobial Fuel CellElectrical

MonitoringElectrical

RegulationFeeding and Case

Design

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Decision-Making Process1. Brainstorm (Group and Individual)2. Discuss Design Requirements3. Research4. Design5. Present Design to Team6. Refine Design7. Present Refined Design to Team8. Order Parts9. Assembly10. Testing

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

How Microbial Fuel Cells (MFC) Work

Schematic courtesy of Derek R. Lovely Schematic courtesy of Derek R. Lovely (Microbial Energizers: Fuel Cells the Keep Going?)(Microbial Energizers: Fuel Cells the Keep Going?)

Story of Electrons:Anode

• Electrons from Acetate to Geobacter

• Geobacter sends electrons outside itself to electrode

Cathode• Electrons combine

with Oxygen and Protons to form water

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Microbial Fuel Cell DesignSpecies: Geobacter Metallireducens

Most Efficient Colonization and Power DensityWidely tested

Membrane: Cellophane vs NafionBalance Cost and Permeability

Electrode: Carbon Cloth vs Carbon Porous Block

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Anode Cube

Food Input

Waste Output

Electrode Location

(Each Face)

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Power ManagementRegulated

Power Supply

USB Power Switching

AVR Butterfly

3V

5V

Vin

5V

OC

3V

Temperature sense

Power management module

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Regulation

Output: 4.75V-5.25V, 100mA-500mA for USB Compatibility

Step up voltage from 3.0V to 5.0V

Research and Decisions

Maxim MAX1524 Boost Controller

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Regulation

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

GoalMonitor the status of the system and

communicate relevant status to userRequirements

Update user the system status voltage produced by MFC Optimum temperature range 20 – 35 C circuit integrity, for e.g. over-current, short circuit

Use minimum power to monitor the systemUser friendlyComponents RoHS compliant and lead free

Monitoring System

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Monitoring System

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Program control logic

Monitoring System

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Program control logic

Monitoring SystemAVR butterfly kit

Atmega169 micro-controller

Low power consumption: < 500µA

RoHS compliantWinAVR for coding &

compilingAVR Studio for

debugging and loading code

Block diagram

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Feeding and Waste System

Food Solution BladderReplaced by User Periodically

CathodeTank

Waste TankEmptied by User Periodically

Anode Cube

Anode Cube

Anode Cube

Anode Cube

Introduction Microbial Fuel Cells Feeding/CaseRegulation Monitoring

Conclusion

Achieved Goal of Advancing Existing Designs Toward Feasible Product

Future ProjectsProduce Smaller Cube: Fabrication MethodsFull Testing of Cellophane MembranePlatonized Electrodes to Allow Air Cathode

Acknowledgements Professor Ray Hozalski, Civil Engineering, University of Minnesota – Twin Cities, for

samples/supplies of electrodes, membranes, and information on MEAs. Chris Harrington, Graduate Student Researcher, University of Minnesota – Twin Cities,

for help with implementation procedures. Professor John Wertz, Biology Department, for assistance in Microbiology growth and

experimentation. Professor J. Aubrey Sykes, Engineering Department, for his ongoing role as the senior

design advisor and for all of this feedback about our project. Professor Randall Brouwer, Engineering Department, for supplying VHDL code for ADC

interface. Sam Brower, Media Productions Calvin Alum, for various visual design and photographic

assistance. Bob DeKraker, Engineering Department, for logistical support with procurement of

circuit components. Rich Huisman, Chemistry Department, for assistance with salt bridge supplies. Lori Keen, Biology Department, for assistance in biological procurement and lab support. Professor Walter Rawle, Engineering Department and Senior Design Team Mentor, for

meeting with our team and assisting us with the in progress reviews. Professor Gemma Reguera, Michigan State University, for providing technical

information and expertise.