Before we build our EMF bug detector, we want to make sure that the LCD screen is working correctly. Therefore, we are going to test it by printing a very simple message on it.

The following is a complete sketch to do this:

// Required libraries
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Create LCD instance
LiquidCrystal_I2C lcd(0x27,20,4);

void setup()
{
  // Initialise LCD
  lcd.init();
 
  // Print a message to the LCD
  lcd.backlight();
  lcd.setCursor(0,0);
  lcd.print("Hello Secret Agent!");
}


void loop()
{
}

As you can see, the sketch is pretty straightforward. You can now plug the Arduino project into your computer using a USB cable and then copy and paste the sketch into your Arduino IDE.

Then, upload the sketch to your board. This is what you should see:

If you can see this message, congratulations, you are ready to move to the next step!