Arduino GPIO LED Blink

Solving Approach

How do you plan to solve it?

 Step 1: Select a GPIO Pin

• Choose a digital pin from the Arduino UNO (e.g., D3) to control the LED.

Step 2: Connect the LED Circuit

• Connect the anode (long leg) of the LED to the GPIO pin through a 330Ω resistor.
• Connect the cathode (short leg) of the LED to GND.
• This setup ensures about 10 mA current through the LED (using Ohm’s Law).

Step 3: Set GPIO as OUTPUT

• In the setup() function, use pinMode(led, OUTPUT); to configure the selected pin for output mode.

Step 4: Blink the LED

• Use digitalWrite() inside the loop() to toggle the LED state.
• LED ON for 400 milliseconds → digitalWrite(led, HIGH);
• LED OFF for 800 milliseconds → digitalWrite(led, LOW);
• This timing is controlled using the delay() function.

Step 5: Upload and Test

• Upload the code to the Arduino UNO.
• Verify that the LED blinks with the correct timing and brightness.

Code

/*Paste your code here*/
int led=3;
void setup(){
pinMode(led,OUTPUT);
Serial.begin(9600);
}
void loop(){
digitalWrite(led,HIGH);
delay(400);
digitalWrite(led,LOW);
delay(800);
}

Output

Video

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Photo of Output