[arduino code examples for F8]-11 Digital input trigger relay output

Code:
/*

 * Made by KinCony IoT: https://www.kincony.com

 *

 * This program reads 8 input states from a PCF8575 I/O expander and 

 * controls a corresponding 8-channel relay module. When an input pin 

 * is LOW, the corresponding relay is turned ON (LOW means ON for the relay).

 *

 * Pin Definitions:

 * - SDA: GPIO 8

 * - SCL: GPIO 18

 * - PCF8575 I2C Address: 0x24

 */



#include <Wire.h>

#include <PCF8575.h>



// I2C pins

#define SDA 8

#define SCL 18



// PCF8575 I2C address

#define INPUT_I2C_ADDRESS 0x24   



// Create PCF8575 object

PCF8575 pcf8575_IN(INPUT_I2C_ADDRESS);



void setup() {

  // Initialize I2C communication

  Wire.begin(SDA, SCL);



  // Initialize serial communication

  Serial.begin(115200);

  

  // Initialize PCF8575

  pcf8575_IN.begin();



  // Turn off all relays first (assuming LOW activates the relay)

  for (int i = 8; i < 16; i++) {

    pcf8575_IN.write(i, HIGH);  // Set to HIGH to turn off the relay

  }



  Serial.println("System started: Input state controlling 8 relays");

}



void loop() {

  // Read 16-bit state from PCF8575

  uint16_t inputState = pcf8575_IN.read16(); 



  for (int i = 0; i < 8; i++) {

    bool state = bitRead(inputState, i); // Read digital input state



    Serial.print("DI");

    Serial.print(i + 1);

    Serial.print(" State: ");

    Serial.println(state ? "HIGH" : "LOW");



    // Control relay (LOW activates the relay)

    pcf8575_IN.write(8 + i, state ? HIGH : LOW);

  }



  Serial.println("---------------------");

  delay(500);

}