Arduino code for 4 to 16 channel 5V Relay module

This is code for 4 to 16 channel 5V Relay module for Arduino

In this video you will learn the details description of 4 Channel relay module. You will learn the meaning of lower trigger and high trigger. You will also learn how to connect external load to the relay and isolate the relays from the Arduino . http://robojax.com/learn/arduino/


 /*
This is code to control 4 to 16 channel 5V Relay module using Arduino
 * watch the video on how to use 4 to unlimited Relay channels  https://youtu.be/Wbm3MCMgM_s
 
 */
/*
 *  This code is written by Ahmad Shamshiri for Robojax.com
// Written Mar 26, 2018 at 12:14 in Ajax, Ontario, Canada

 *  
 */

int ch = 4;// number of relays you got
int relay[]={2,3,4,5}; // Arduino pin numbers. the same number of relay should be defined here as input pins


int wait = 2000;// delay time
int i=0;

void setup() {
    Serial.begin(9600);// prepare Serial monitor
    // set  pins as output
 for(i=0; i < ch; i++)
 {    
    pinMode(relay[i], OUTPUT);// sent i(th) pin as output
   digitalWrite(relay[i], HIGH); // Turn the relay OFF  
 }
               
    Serial.println("Robojax 4 Relay Test");
}

void loop() {
    
     
 for(int i=0; i < ch; i++)
 {
      Serial.print("Relay "); Serial.print(i+1);Serial.println(" ON");
      digitalWrite(relay[i], LOW); // Turn the relay ON    
      delay(wait);  
 }// for loop


 for(int i=0; i < ch; i++)
 {
      Serial.print("Relay "); Serial.print(i+1);Serial.println(" OFF");
      digitalWrite(relay[i], HIGH); // Turn the relay OFF    
      delay(wait);  
 }// for loop

    Serial.println("====== loop done ==");

}// loop

If you want to replace the loop inside setup(), then use this as shown in video


 
    pinMode(relay[0], OUTPUT);// connected to relay1
    digitalWrite(relay[0], HIGH); // Turn the relay OFF  


    pinMode(relay[1], OUTPUT);// connected to relay2
    digitalWrite(relay[1], HIGH); // Turn the relay OFF  

    pinMode(relay[2], OUTPUT);// connected to relay3
    digitalWrite(relay[2], HIGH); // Turn the relay OFF  

    pinMode(relay[3], OUTPUT);// connected to relay4
    digitalWrite(relay[3], HIGH); // Turn the relay OFF