1. Hall Effect Sensor ME207 – Advanced Mechatronics I Steven Li 10-19-2009

2. Background Magnetic field sensor based on Hall Effect Hall Effect Discovered in 1879 by Edwin Hall Applications: ▫Current sensor ▫Analog multiplication ▫Position/Motion sensing ▫Spacecraft propulsion (HET) Edwin Hall, 1855-1938

3. Operating Principles Lorentz force: Accumulation of charge on conductor produces Hall Voltage: In semiconductors (InAs): (source: http://en.wikipedia.org/wiki/File:Hall_effect.png) 1. Electrons 2. Hall element, or Hall sensor 3. Magnets 4. Magnetic field 5. Power source

4. Implementation Common digital Hall Effect Sensor IC package ▫Current source, Hall Element, Differential Amplifier, Schmitt Trigger Magnet/HES arrangements ▫Example: window/tab vs. magnet wheel Quadrature arrangement packages allow for direction sensing (source: http://www.sparkfun.com/datasheets/Sensors/Magneto/ATS177.pdf)

5. Tradeoffs & Applications Advantage over optical/contact encoders as position sensor Voltage isolation as current sensor Must be used in couple with magnets Position/Rotation sensing Tachometer Gear tooth sensor Anti-lock brake systems/traction control systems HDD precision servo Ignition firing timing Extreme environment H/I (JS, keyboard, etc) Power sensing (analog multiplication) Hall Effect Thruster