The AH1815 is an integrated Hall-Effect non-latched sensor. That’s nice but what does it do? Holding a magnet near the sensor will cause the output pin to toggle. This makes for a robust presence sensor. A reed sensor also works nicely, but can be limited by the glass encapsulation and size. A Hall-Effect sensor is much smaller, and can handle less current than a reed switch.

The AH1815 is a low-sensitivity, micro-power Omnipolar Hall effect switch IC, designed for portable and battery powered consumer equipment for home appliance and industrial applications. To support portable and battery powered equipment, it was designed to operate over the supply range of 2.5V to 5.5V and consumes only 24µW .

The single open drain output can switch on with either a north or south pole of sufficient strength. When the magnetic flux density (B) perpendicular to the package is larger than operating point (Bop) the output is switched on (pulled low). The output is turned off when B becomes lower than the releasing point (Brp). The output will remain off when there is no magnetic field.

Features

• Omnipolar (North or South pole) Operation
• 2.5V to 5.5V Operating Range
• -40°C to +125°C Operating Temperature
• Micropower Operation
• Superior Temperature Stability Minimal Switch Point Drift Enhanced Immunity to Stress

AH1815 hall effect sensor datasheet.