Connect the inductive proximity sensor to the digital input pin of Arduino.

Setup the necessary inputs and outputs related to your project.

Use loop()

and use digitalRead(input pin of the sensor) to carry out necessary commands in the loop.

You should connect your sensor to a digital input. but you need to measure the frequency. this is done using the pulse in function as it is here https://www.instructables.com/Arduino-Frequency-Counter/

Or another approach is to use the port manipulation read to poll the digital input as in the code below.

also below, for frequencies lower than 20Hz the millis() function is used, and for frequencies higher than 20Hz the micros() function is used. The input pin is digital pin 9 or PB1, hence PINB&2

https://www.electronicshub.org/wp-content/uploads/2021/01/Arduino-UNO-Pinout.jpg

#include

uint8_t address = 80;

uint8_t sda = 4;

uint8_t scl = 3;

int input=12;

#define echoPin 9

int pin_mode = 7;

double frequency;

double f;

double duration ;

double counter ;

unsigned long time;

int dist;

char freq[10],dst[10];

Soft_Lcd_I2C i2cLcd( address, 16, 2, sda, scl );

void setup()

{

Serial.begin(19600);

pinMode( 13, OUTPUT );

i2cLcd.init();

pinMode(input, INPUT);

pinMode(pin_mode, INPUT);

pinMode( echoPin, INPUT );

}

float freq2()

{

duration = 0;

counter = 0;

while ( --counter != 0 )

if ( (PINB & 2) == 0 )

break;

while ( --counter != 0 )

if ( PINB & 2 )

{ time = millis();

break;

}

while ( --counter != 0 )

if ( (PINB & 2) == 0 )

break;

while ( --counter != 0 )

if ( PINB & 2 )

{

duration = millis() - time;

break;

}

return 1000 / duration ;

}

float freq3()

{

duration = 0;

counter = 0;

while ( --counter != 0 )

if ( (PINB & 2) == 0 )

break;

while ( --counter != 0 )

if ( PINB & 2 )

{

time = micros();

break;

}

while ( --counter != 0 )

if ( (PINB & 2) == 0 )

break;

while ( --counter != 0 )

if ( PINB & 2 )

{

duration = micros() - time;

break;

}

return 1000000 / duration ;

}

void loop()

{

f=freq2();

frequency=f;

if (f>20)

f =freq3() ;

Serial.print("frecventa2=");

Serial.println(f);

}