Mid-Semester Design Presentation Senior Design Presentation October 1, 2009 Contactless Angular Position Sensor

Team Members Eugene Sandberg Computer Engineer Tasks: -Construct Test Setup -Program Microchip 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 Solution Constraints – Technical – Practical Alternatives Progress

Problem and Solution Problem Statement The current sensor fails due to shaft mechanical contact. Each failure results in a significant cost for the Army since they must replace the entire A-Arm. Solution Eliminate the mechanical contact by using a Hall effect sensor and a magnet attached to the rotating portion of the A-Arm. The raw data output will be processed by the PIC24 and sent to the output stage for amplification. A test setup will be constructed that will allow us to test the chosen sensors and magnets. Finally, a mechanical prototype will be constructed using a 3D CAD program.

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

Constraints Technical Constraints Practical Constraints

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.

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 24 ms or less.

Practical Constraints Problem Sustainability – The CAPS must be contactless.

Practical Constraints Problem Manufacturability – The design must be easily produced and manufactured by an army subcontractor. – Must Fit in End Cap – Same Casing

Optical -Grease Interference -Outside of Vehicle -Particle Interference WiFi/Bluetooth -Complicated -Extra Power Source Alternatives

Magnet A (Largest Magnet) 45 Degrees90 Degrees135 Degrees 5mm mm mm mm mm mm Magnet B (Second Largest Magnet) 45 Degrees90 Degrees135 Degrees 5mm mm mm mm mm mm Magnet C (Third Largest Magnet) 45 Degrees90 Degrees135 Degrees 5mm mm mm mm mm mm Magnet D (Smallest Magnet) 45 Degrees90 Degrees135 Degrees 5mmDATA INCONSISTINT MAGNET TOO WEAK 10mmDATA INCONSISTINT MAGNET TOO WEAK 15mmDATA INCONSISTINT MAGNET TOO WEAK 20mmDATA INCONSISTINT MAGNET TOO WEAK 25mmDATA INCONSISTINT MAGNET TOO WEAK 30mmDATA INCONSISTINT MAGNET TOO WEAK Magnet Comparison

Alternatives Sensors, MAX548A, and PIC24 for Test and Implementation MLX90316 Rotary Position IC Hall Technology Output Signal to PIC PIC24 Process Sensor Signal Talks to the MAX548A KMA200 Analog Output Will be used for initial testing, Calibration of Test Setup MAX5312EAE DAC 5V-10V LM7321MA OP AMP Will output voltage of 0- 24

Progress Test Setup Built Simulation Control Arm from PVC Mounted Arm on Test Bench Attached Magnet to Rotating Portion of Arm Mounted Sensor Setup Facing Magnet -Sensor setup will consist of PIC24HJ64, a Hall Effect sensor, and the necessary circuitry Mounted Old Sensor on Backend for Comparison

Progress Tasks/Dates

References [1] Karahalis, Alex. “Contacless Angular Position Sensor.” August 11, [2] SPG Media Group Ltd. “Stryker 8-Wheel Drive Armoured Combat Vehicles, USA.” [Online]. Available: [Accessed: August 30, 2009].

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