The Melexis MLX90217 is a digital gear-tooth hall effect sensor designed for use in automotive camshaft sensing as well as other speed sensing applications. It is designed to be used with a magnet to sense the rotating speed (incremental position) of a ferrous tooth-wheel.
Hall-effect gear-tooth sensors detect changes in a magnetic field. When a gear tooth or other ferrous object approaches a magnet, it distorts the field surrounding that magnet. The presence or absence of ferrous gear tooth are detected by measuring this distortion. The most common method of measurement places a sensor on one magnet poles, and observes an increase in the magnetic field as a target approaches the pole.
Parallax reported using the Melexis 90217 sensor in applications including CNC milling machine spindle speed measurement and feedback on motor RPM. With the CNC milling machine it reliably measured the top spindle speed of 7,500 RPM.
Features
- On-chip 10 bit A/D converter
- Self-adjusting magnetic range
- Voltage: 3.5-24 VDC
- Micropower Operation
- Current: ~3 mA
- Rotary position gear tooth sensing ability
- High speed operation
- Zero speed detection
Applications
- Gear tooth rotation speed detection
- Shaft rotation speed detection
- Proximity detection
