B & B

Make an LED turn on and off periodically using an Arduino and a few simple components.

What you'll need:

• 1 Arduino board (Uno or similar)
• 1 LED
• 1 220Ω resistor
• 1 breadboard
• 3 jumper wires
• 1 USB cable to connect the Arduino to your computer

Wiring:

1. Place the LED on the breadboard. Note which leg is longer (the anode / positive leg) and which is shorter (the cathode / negative leg).
2. Connect the longer leg (positive +) to one end of the 220Ω resistor.
3. Connect the other end of the resistor to pin 13 on the Arduino using a jumper wire.
4. Connect the shorter leg (negative -) of the LED to the ground rail on the breadboard using a jumper wire.
5. Connect the ground rail of the breadboard to the Arduino's GND pin using a jumper wire.

Arduino. (2024, January 30). How are the LEDs represented in the Starter Kit projects book? [Image]. https://support.arduino.cc/hc/article_attachments/12416016395676

Circuit diagram created using Tinkercad (https://www.tinkercad.com/).

Code:

void setup() {
  pinMode(13, OUTPUT);
}

void loop() {
  digitalWrite(13, HIGH);
  delay(1000);
  digitalWrite(13, LOW);
  delay(1000);
}

1. Open the Arduino IDE and paste in the code above.
2. Under Tools, select your board (e.g. Arduino Uno) and the correct port.
(if you are unsure which port to select, disconnect your Arduino and check the list of ports, then reconnect it and see which new port appears)
3. Click Upload.

Söderby, K., & Hylén, J. (2024, January 17). Getting Started with Arduino IDE 2. Arduino Documentation. https://docs.arduino.cc/software/ide-v2/tutorials/getting-started-ide-v2/

Troubleshooting:

Once the upload finishes, the LED should turn on and off once per second. If it isn't working as expected, check the following:

• The longer leg of the LED (anode) should connect toward the resistor side, and the shorter leg (cathode) toward GND.
• The resistor is in place between the LED and pin 13.
• All jumper wires and the LED are firmly seated in the breadboard, in the correct rows.
• The IDE shows "Done uploading" with no red error text in the console after clicking Upload.
• The correct board and port are selected under the Tools menu.
• The USB cable is a data cable, not a charge-only cable.
• The pin number in the code (13) matches the pin you actually wired the LED to.

Video demonstration: