An LED of Your Own

Part of the First Circuits section of Coddy's Arduino journey. Lesson 4 of 22.

So far the LED came wired to pin 13. This one is on pin 8, wired the way every LED is.

An LED lets current through in one direction only. Its long leg, the anode (+), goes to the pin. Its short leg, the cathode, goes towards GND, short for ground: the board's 0 volts.

Between the LED and ground sits a resistor. It limits the current, the flow of electricity. Without it the LED lets far too much current through and can burn out, and damage the pin too.

The LED uses about 2V of the pin's 5V, and the 220 ohm resistor takes the other 3V. 3V divided by 220 ohm is about 14 mA (thousandths of an amp): bright enough to see, and under the 20 mA a pin should give.

Challenge

Easy

The red LED is wired to pin 8 through a 220 ohm resistor. Make it blink:

make pin 8 an output in setup()
in loop(), turn it on, wait, turn it off, wait (any speed you like)

Press Run to watch it, then Check.

Try it yourself

void setup() {
  // make pin 8 an output
}

void loop() {
  // blink the LED on pin 8
}

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in First Circuits

1Hello, Board

Blink an LED Setup and Loop Change the Blink SpeedAn LED of Your OwnTwo LEDs Taking Turns Comments in Your Sketch

4Decisions

Decisions with if Choosing with if and else Comparing Values Combining Conditions Read a Button

2Talking to Your Computer

Hello, Serial Monitor Print Versus Println Printing Numbers Your First Variable Counting Up When an Int Runs Out

3Math on the Board

Named Constants Arithmetic Operators Integer Division Decimals with float A Blink That Speeds Up

Practice on your own: Arduino playground