Honeywell SS343RT Unipolar Hall Effect Magnetic Sensor - SOT-23-3 SMD

A unipolar sensor, like the SS343RT, activates its output only when exposed to a magnetic field of a specific polarity (typically a south pole) and deactivates when the field is removed. A bipolar sensor responds to both north and south poles, often toggling its output state with each pole reversal, which is useful for speed sensing in rotating applications.

The SS343RT features an open-collector digital output. An external pull-up resistor (typically between 1kΩ and 10kΩ) must be connected between the output pin and the positive supply voltage (Vdd) to provide a logic-high level when the sensor is off. The resistor value should be chosen based on your system's required switching speed and current consumption.

Yes. When powered within its 3-24V range (use 5V for Arduino, 3.3V for Raspberry Pi with a logic-level shifter if needed), the sensor's digital output can be connected directly to a GPIO input pin. Remember to add the external pull-up resistor to the output line as described in the datasheet for proper signal conditioning.

Choose a magnet whose magnetic field strength at the intended sensing distance falls within the sensor's 45 G to 205 G operating point (Bop) range. You must also ensure the correct magnetic polarity (south pole facing the branded side of the sensor is typical). Testing with a gaussmeter or prototyping is recommended to confirm reliable switching at your specific air gap.