LED Blink

Solving Approach

How do you plan to solve it?

 
 I usually separate this kind of problems in two: Hardware and  firmware 

Hardware: Let´s find the resistance value that allows a 10mA flowing through the LED

Vin = 5v, Vd = 1.8v   ---->     Vr = 5v - 1.8v = 3.2v

R = Vr / Ir  = 3.2v / 10mA = 320 ohms  -----> 330 ohms

Code

/*Paste your code here*/
const int led = 7; // I USED A CONSTANTE VARIABLE TO AVOID UNDESIRED CHANGES

void setup() {
  pinMode(led, OUTPUT);
  digitalWrite(led,LOW); // I inicialized my led pin in Low state
}

void loop() {

   digitalWrite(led,HIGH);
   delay(400);
   digitalWrite(led,LOW);
   delay(800);
}

Output

Video

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Photo of Output

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