1. Arduino Uno R3 - The primary microcontroller board that will control the LED.
2. LED (Light Emitting Diode) - The visual indicator that will blink.
3. Resistor (220 Ohms to 1k Ohm) - To limit the current through the LED and prevent it from burning out. (Assuming a typical LED forward voltage of approximately 2V and a forward current of about 20mA, a value within this range would suffice. I'll use a 220 Ohm resistor for calculations.)
4. Jumper wires - To make connections between components.

1. Add Arduino Uno R3: Place the Arduino Uno R3 on your schematic.
2. Add LED: Place an LED on your schematic.
3. Add Resistor: Place a 220 Ohm resistor on your schematic. This value is to ensure we're within safe operating conditions for the LED given the 5V output from the Arduino.
4. Add Jumper Wires as needed to connect the components.

• Connect the Arduino Uno R3 digital I/O pin (let's choose pin 13 for its built-in LED driving capability) to the anode (longer lead) of the LED. This connection will control the LED.
  • Connect Arduino Uno R3:D13 to one side of the resistor (Resistor can be placed in series with LED in any order).
• Connect the other side of the resistor to the anode of the LED.
  • Connect Resistor:1 to LED:Anode.
• Connect the cathode (shorter lead) of the LED to one of the GND pins on the Arduino Uno R3 to complete the circuit.
  • Connect LED:Cathode to Arduino Uno R3:GND.

Cpp
// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);                       // wait for a second
}