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

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Code:

/*
* PCF8574 Relay Control Example
*
* Controls 5 relays connected to PCF8574 via I2C bus.
*
* Made By KinCony
* https://www.kincony.com
*/

#include <Arduino.h>
#include <Wire.h>
#include "PCF8574.h"

// I2C pin definitions
#define I2C_SDA 8
#define I2C_SCL 18

// Create PCF8574 object with I2C address 0x26
PCF8574 pcf8574(0x26);

void setup() {
  Serial.begin(115200);
  delay(500);

  // Initialize I2C with specified SDA and SCL pins
  Wire.begin(I2C_SDA, I2C_SCL);

  // Set PCF8574 P3~P7 as OUTPUT (Relays)
  pcf8574.pinMode(P3, OUTPUT);
  pcf8574.pinMode(P4, OUTPUT);
  pcf8574.pinMode(P5, OUTPUT);
  pcf8574.pinMode(P6, OUTPUT);
  pcf8574.pinMode(P7, OUTPUT);

  Serial.print("Init pcf8574...");
  if (pcf8574.begin()) {
    Serial.println("OK");
  } else {
    Serial.println("KO");
    while (1); // Stop if initialization fails
  }

  // Turn OFF all relays at startup
  for (int pin = P3; pin <= P7; pin++) {
    pcf8574.digitalWrite(pin, LOW);
  }
}

void loop() {
  // Turn ON all relays one by one
  for (int pin = P3; pin <= P7; pin++) {
    pcf8574.digitalWrite(pin, HIGH);
    delay(500);
  }

  delay(1000); // Keep all relays ON for a while

  // Turn OFF all relays
  for (int pin = P3; pin <= P7; pin++) {
    pcf8574.digitalWrite(pin, LOW);
  }

  delay(1000); // Keep all relays OFF for a while
}

arduino ino file download:

  1-relay.zip (Size: 724 bytes / Downloads: 145)
BIN file (you can use esp32 download tool download to ESP32-S3 with address 0x0 then directly to use) download:

  1-relay.ino.merged.zip (Size: 198.37 KB / Downloads: 132)