Learn ESP32, ESP8266, Arduino, and Raspberry Pi

Blinking LED

We can start with a simple project to learn the basic operation and code in the Arduino IDE.

Basics: Project 012a

Project name: Blinking LED

Sketch: sketch


  • None

In this project, you needed these parts :

1.Arduino Uno R3 (you can also use the other version of Arduino)

2.Arduino IDE ( you can download it from here  )

3.Jumper cables

4. LED 1 pc

5. Resistor 1 pc (220 Om)

6. Breadboard

Signals and connections of LED

The operating voltage of the LED is 1.8V and the operating current is 10mA-20mA. The Arduino Uno board can supply 5V or 3.3V power. We will use 5V for this project, so the minimum resistance of the current limiting resistor should be (5 V to 1.8 V)/20 = 160 Om. The 220 Om offered in the kit is suitable and you can also choose other resistors that meet the condition. The larger the resistance is, the dimmer the LED will get.


Connect one end of the 220 Om resistor to pin 10 of the Arduino Uno board and the other end to the anode (the long pin) of the LED, and the cathode (the short pin) of the LED to GND. When the pin 10 outputs high level, the current gets through the current limiting resistor to the anode of the LED. And since the cathode of the LED is connected to GND, the LED will light up.  When pin 10 outputs low level, the LED goes out.

The following picture shows the needed connections with the Arduino Uno 

Step by Step instruction

  1. Plug your Adruino Uno board into your PC and select the correct board and com port
  2. Open up serial monitor and set your baud to 9600 baud
  3. Verify and upload the the sketch to your Adruino Uno
  4. You should now see the LED blinking


Through this project, you have learned how to turn on an LED. You can also change the blinking frequency of the LED by changing the num value in the delay function delay (num). For example, change it to delay (250) and you will find that the LED blinks more quickly. 

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