How to connect Arduino uno to relay module very simple

This article shows how to control mains voltage with the Arduino using a relay module. We make a brief introduction to the relay module and build a simple project example with the Arduino. The example we’ll build shows how to control a relay module with an Arduino and a simple project.

Hardware Required

Arduino or Genuino 
BoardRelay module
Male & Female jumpers

• You can connect the wire of light -

Arduino uno - Relay module

8                     - IN1(Relay 1)

9                     - IN2(Relay 2)

GND              - GND(Control)

5V                  - VCC(Power)

Code

int ledone = 8;

int ledtwo = 9;

void setup() {  

  pinMode(ledone, OUTPUT);

  pinMode(ledtwo, OUTPUT);

}

// the loop function runs over and over again forever

void loop() {

   digitalWrite(ledone,HIGH);                         

   digitalWrite(ledtwo,HIGH);

   delay(1000);                       // wait for a second

   digitalWrite(ledone,LOW);                         

   digitalWrite(ledtwo,LOW);

   delay(1000);                       // wait for a second

}