Mid-Semester Design Presentation Senior Design Presentation October 8, 2009 Contactless Angular Position Sensor

Team Members Eugene Sandberg Computer Engineer Tasks: -Construct Test Setup -Program Microchip -Website Christine Bratton Electrical Engineer Tasks: -Research Magnets and Sensors -Program Microchip -Output Stage Aram Lee Electrical Engineer Tasks: -Research Magnets and Sensors -Program Microchip Jeremy Lewis Computer Engineer Tasks: -Construct Test Setup -Packaging -Layout Matt Landry Electrical Engineer Tasks: -Research Magnets and Sensors -Output Stage -Packaging

Outline Problem Statement Solution Diagram Constraints – Technical – Practical Alternatives to Original Solution Progress –Timeline

Problem Endcap/SensorA-Arm

Problem With Current Design The current sensor fails often. The Army believes that it is due to the mechanical contact.

Solution - Hall Effect Sensor

Overview of Proposed Solution Magnet Generates a magnetic field. Sensor Outputs a signal relative to angular position of magnetic field. Microprocessor Processes the signal from the sensor. DAC/Amp Outputs analog voltage. (0-24V)

Constraints Technical Constraints Practical Constraints

Technical Constraints The CAPS must be driven by a 24 volt input and output a linear DC voltage ranging from 0 to 24 V. The CAPS must draw less than 24 mA. The CAPS must have a response time of less than 20ms or less.

Technical Constraints The CAPS must operate between -40 to 70 degrees Celsius The CAPS must be accurate to.1 degrees and measure an angle of 90 degrees.

Practical Constraints Problem Sustainability – The CAPS must be contactless.

Practical Constraints Problem Compatibility – Must Fit in End Cap – Same Casing

Optical -Grease Interference -Outside of Vehicle -Particle Interference Alternatives for Angular Position Sensing

Hall Effect Sensor -No particle interference -Operates in Endcap -Sensitive to Magnetic field Alternatives for Angular Position Sensing

Alternatives Angular Position Sensors MLX90316 Hall Technology Digital SPI Output Specify Default Mode when Ordering Currently Being Tested 360 Degree Range KMA200 Magnetoresistive Analog and Digital SPI Output Default Mode is Analog Will be used for Initial Testing, Calibration of Test Setup 180 Degree Range

Progress - Parts MAX5312EAE DAC 0V-8V Output 12Bit Percision LM7321MA OP AMP 3 to 1 Amplification Will output voltage of V supply PIC24 Process Sensor Signal Talks to the MAX5312EAE

Progress-Test Setup Test Setup

Progress Magnet A (Largest Magnet) Voltage at 45 Degrees Voltage at 90 DegreesVoltage at 135 Degrees 5mm mm mm mm mm mm Magnet Evaluation

Progress Timeline

References Karahalis, Alex. “Contacless Angular Position Sensor.” August 11, SPG Media Group Ltd. “Stryker 8-Wheel Drive Armoured Combat Vehicles, USA.” [Online]. Available: [Accessed: August 30, 2009]. Quasdorf, Joachim. “A Case Study: MR vs. Hall Effect for Position Sensing.” [Online]. Available: [Accessed: October 2009].

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