[arduino code examples for F24]-01 Turn ON/OFF relay

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Code:

/*
* Made by KinCony IoT: https://www.kincony.com
*
* This program controls a 24-channel relay board via two PCF8575 I/O expanders.
* It sequentially turns on each relay and then turns them off in a loop.
*
* Pin Definitions:
* - SDA: GPIO 8
* - SCL: GPIO 18
*
* Delay Time:
* - 200 milliseconds between switching relays
*/

#include <Wire.h>        // Include the Wire library for I2C communication
#include <PCF8575.h>     // Include the PCF8575 library to control the I/O expander

#define SDA 8            // Define the SDA pin
#define SCL 18           // Define the SCL pin
#define DELAY_TIME 200   // Define the delay time in milliseconds

// Set I2C addresses of the PCF8575 modules
#define I2C_ADDRESS_R1 0x25 // I2C address of the first PCF8575 module
#define I2C_ADDRESS_R2 0x26 // I2C address of the second PCF8575 module

PCF8575 pcf8575_R1(I2C_ADDRESS_R1); // Create a PCF8575 object for the first module (for relays 9-24)
PCF8575 pcf8575_R2(I2C_ADDRESS_R2); // Create a PCF8575 object for the second module (for relays 1-8)

void setup() {
  // Initialize I2C communication
  Wire.begin(SDA, SCL); // SDA on GPIO 8, SCL on GPIO 18 (according to your board's configuration)
 
  // Initialize serial communication for debugging (optional)
  Serial.begin(115200);
  Serial.println("PCF8575 Relay Control: Starting...");

  // Initialize the PCF8575 modules
  pcf8575_R1.begin();
  pcf8575_R2.begin();

  // Turn off all relays initially (set all pins HIGH)
  for (int i = 0; i < 16; i++) {
    pcf8575_R1.write(i, HIGH); // Set relays 9-24 to OFF (assuming HIGH means OFF for relays)
    pcf8575_R2.write(i, HIGH); // Set relays 1-8 to OFF (assuming HIGH means OFF for relays)
  }
}

void loop() {
  // Sequentially turn on each relay (1-24)
 
  // First control the relays on the second PCF8575 (relays 1-8, corresponding to pins 8-15)
  for (int i = 8; i < 16; i++) {
    pcf8575_R2.write(i, LOW);   // Turn on the relay at pin i (LOW means ON for the relay)
    delay(DELAY_TIME);          // Wait for DELAY_TIME milliseconds
  }

  // Then control the relays on the first PCF8575 (relays 9-24)
  for (int i = 0; i < 16; i++) {
    pcf8575_R1.write(i, LOW);   // Turn on the relay at pin i (LOW means ON for the relay)
    delay(DELAY_TIME);          // Wait for DELAY_TIME milliseconds
  }

  // Sequentially turn off each relay (1-24)
 
  // First control the relays on the second PCF8575 (relays 1-8, corresponding to pins 8-15)
  for (int i = 8; i < 16; i++) {
    pcf8575_R2.write(i, HIGH);  // Turn off the relay at pin i (HIGH means OFF for the relay)
    delay(DELAY_TIME);          // Wait for DELAY_TIME milliseconds
  }

  // Then control the relays on the first PCF8575 (relays 9-24)
  for (int i = 0; i < 16; i++) {
    pcf8575_R1.write(i, HIGH);  // Turn off the relay at pin i (HIGH means OFF for the relay)
    delay(DELAY_TIME);          // Wait for DELAY_TIME milliseconds
  }
}

arduino ino file download:

  1-relay.zip (Size: 1.03 KB / Downloads: 16)