Linear Hall magnetic module and a digital interface, built-in 13 LED build a simple circuit to produce a magnetic field warning lamp 13 comes with digital interfaces of the LED, the linear Hall sensor magnetometer access number 3 interface, when linear Hall magnetometer Sensor senses a key signal, LED lights, otherwise off.
The following is the routines source code for your reference.
int Led = 13 ;// define LED Interface
int buttonpin = 3; // define the linear Hall magnetic sensor interface
int val ;// define numeric variables val
void setup()
{pinMode(Led, OUTPUT) ;// define LED as output interface
pinMode(buttonpin, INPUT) ;// define linear Hall magnetic sensor output interface}
void loop ()
{val = digitalRead(buttonpin) ;// digital interface will be assigned a value of 3 to read val
if(val == HIGH) // When the linear Hall sensor detects a magnetic signal, LED flashes
{digitalWrite(Led, HIGH);}
else
{digitalWrite (Led, LOW);}
}