Buy this 37 in 1 kit.
KY-035 is an analog magnetic field sensor module. The strength of the field is given by an analog voltage at the signal pin of the module KY-035. The sensor is connected to gnd and 5V of the Arduino board. The output voltage is measured by analog pin A5 on the Arduino board.
The example program measures the output voltage of the sensor en presents the measured value in the serial monitor of the Arduino.
The led on the board flashes in a speed depending on the strength of the magnetic field. With a small magnet this can be demonstrated.
Example Code /* KY-035 Hall analog sensor */
int sensorPin = A5; // select the input pin
int ledPin = 13; // select the pin for the LED
int sensorValue = 0; // variable to store the value coming from the sensor
void setup () {
pinMode (ledPin, OUTPUT);
Serial.begin (9600);
}
void loop () {
sensorValue = analogRead (sensorPin);
digitalWrite (ledPin, HIGH);
delay (sensorValue);
digitalWrite (ledPin, LOW);
delay (sensorValue);
Serial.println (sensorValue, DEC);
}