I cannot upload my program to an Arduino Nano due to a loop definition error code

Question

I was tasked with a college project which involved programming an Arduino board to flash two LEDs , which would display a number in binary code. I am about halfway through, but when I attempt to upload the program it keeps flashing the following error message. I have attached the code I have written so far and the error message below.

 void setup()
{
  // Set pin D2 as a digital output to control the LED
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
}

// The loop routine runs over and over until the power is switch off.
void loop()
{
  digitalWrite(2, HIGH); // Turn the LED on
  delay(1000);           // 1000 ms delay
  digitalWrite(2, LOW);  // Turn the LED off
  delay(1000);           // 1000 ms delay
 }
void loop()
{
  digitalWrite(3, LOW);
  delay(10000);
  digitalWrite(3, HIGH);
  delay(5000);
  digitalWrite(3, LOW);
  delay(2000);
digitalWrite(3, HIGH);
delay(1000);
digitalWrite(3, LOW);
delay(1000);
digitalWrite(3, HIGH);
delay(1000);
digitalWrite(3, LOW);
delay(8000);
digitalWrite(3, HIGH);
delay(8000);
digitalWrite(3, LOW);
delay(4000);
digitalWrite(3, HIGH);
delay(1000);
digitalWrite(3, LOW);
delay(5000);

Error:

C:\Users\matth\OneDrive\Documents\Arduino\flash\flash.ino: In function 'void loop()':
C:\Users\matth\OneDrive\Documents\Arduino\flash\flash.ino:21:6: error: redefinition of 'void loop()'
 void loop()
      ^~~~
C:\Users\matth\OneDrive\Documents\Arduino\flash\flash.ino:14:6: note: 'void loop()' previously defined here
 void loop()
      ^~~~

exit status 1

Compilation error: redefinition of 'void loop()

I tried removing the second void loop command, and also moving the digital input designation from between the two loops to above the first. However, I have no experience whatsoever with programming so I don't really know how to troubleshoot.

Answer 1

You have 2 loop functions - you can only have one. Remove one and it should compile and load fine.

Then it is just a matter of doing whatever you want it to do in the loop codewise.

• Currently look like one loop is to turn on/off pin 2.

• The other loop setting pin 3 high and low with various delays between the on/off

• more information on how you are expecting the value to be flown on the pins would be needed.