Hall Effect Sensor

Hall effect sensors detect whether a magnet is near. Useful for non-contact/waterproof type switches, position sensors, rotary/shaft encoders.

Runs at 3.5V up to 24V. To use connect power to pin 1 (all the way to the left), ground to pin 2 (middle) and then a 10K pull up resistor from pin 3 to power. Then listen on pin 3, when the south pole of a magnet is near the front of the sensor, pin 3 will go down to 0V. Otherwise it will stay at whatever the pullup resistor is connected to. Nothing occurs if a magnet's north pole is nearby (unipolar).

Example Project

The purpose of this project is to demo the usage of Hall Sensor. When the magnet is close to Hall sensor, the LED-L on Arduino will turn on, and the LED will turn off when the magnet is removed.

List of Components:

Item	Quantity
Arduino Duemilanove or Uno	1
Hall Sensor	1
USB Cable with type A Interface	1
Mini Breadboard	1
Jumper Wire with Male Header	3
Resister with value 10K ohm	1
PC	1

Schematics:

Hardware:

Components needed for the project

Wiring Picture

When there is no magnet close to the Hall sensor, the LED-L will remain off.

When magnet is close to the Hall sensor, the LED-L will turn off.

Pin 3 of hall sensor is connected to D12. D12 will detect the voltage level of D12 to judge if there is magnet close to it. The result will be displayed on LED-L which is controlled by D13.

Code:

<syntaxhighlight lang="c">

int ledPin = 13; int out = 12;

void setup() {

  pinMode(ledPin, OUTPUT); 
  pinMode(out, INPUT);    

}

void loop() {

   if ( digitalRead(out) )    

{

          digitalWrite(ledPin,LOW ); 

}

  else

{

        digitalWrite(ledPin,HIGH); 

} }

</syntaxhighlight>

Resources

• Datasheet