BRAAD Bio Robotic Autonomous Aquatic Demonstration

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BRAADBio Robotic Autonomous Aquatic Demonstration

• Uzma Alam and Danielle Osler
• ECE 345
• Group 9

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Background

• Weakly Electric Fish
• Generate and detect Electric fields
• Electro receptive
• Ability to sense Electric Fields
• Monitor changes in receptors on skin
• On the order of milli-volts
• Passive Sensing

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Objective

• Principal deliverables
• Accurate sensing
• Autonomous movement
• Simulate the passive sensing of electroreceptive
  fish
• Modify an RC boat and add autonomous
  functionality

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Original Design
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Original Design
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Sensors
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Sensor Theory

• Two Possible Configurations
• EKG Sensors
• Need to use sensors in pairs
• Use second configuration

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Sensor Testing
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Amplification
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Amplification

• Use High Precision Instrumention Amps
• Options AD524, LM741, LF357N
• Documented applications Analog signals
• Heart rate Frequency .05Hz to 150 Hz
• Pulse on finger Frequency starts at .03 Hz
• A to D can take 20 mV and convert it
• Use more precise sensing for Microcontroller

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Amplification

• Final Sensor Configuration

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Microcontroller
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Microcontroller Flowchart
Motorola HC12 Assembly Language
Power Up A/D Sets Initial PWM for Motor/Steering
Start
Initialize
Sets ATDCTL5 to 8 bit conversion Samples and
stores digital values
GetAtoD
Linear compare of voltage difference
CompVolt
Updates duty cycle of Steering PWM
Update
Uses RTI to sample A/D every 0.25s
Delay
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Microcontroller Testing

• A/D Conversion
• Accurate to 2 lsb
• Possible to use un-amplified signal

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Motor and Steering
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Motor and Steering Control

• Servos
• Steering TS-11 Microservo
• Motor Hitec HT7001A

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Motor and Steering

• Interface Boards
• Toggle between uC and receiver
• Power from receiver voltage regulator

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Motor and Steering

• Pulse Width Modulation

Reverse
Motor
Forward
Left
Steering
Right
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Power
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Power Theory

• All power from one battery
• Simulations

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Power Design
Connect all components to the same common
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Final Product
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Physical Layout
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Results

• Successes
• Communication Between Modules
• Unique Solution to EKG sensing
• Teamwork

• Challenges
• Amplification of DC signals
• Size reduction
• Physical construction

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Recommendations

• Amplify signals
• Add smoother turning capability
• Add Stop functionality
• Make boat smaller
• Add more sensors

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Acknowledgements

• Professor Nelson
• Professor Swenson
• Julio Urbina
• Braad

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The End