So far we got to know how to install & configure Arduino for ESP8266 programming in a recent article. Now here we will look into the very basic programming part, to blink onboard LED on NodeMCU ESP8266 located near USB port. This can also be used to test the board in general, as you don’t need any external component other than a micro USB cable to connect it to the computer.

REQUIREMENTS

• NodeMCU ESP8266 Board
• Micro USB Cable
• Arduino IDE with ESP8266 board definitions & drivers installed

GETTING READY

To blink onboard LED is as simple as 1, 2, 3 on this NodeMCU ESP8266 board as its self sufficient with everything on it. Detailed steps for the initial setup can be found here. Also note that there are two blue LEDs on board, one near WiFi chip for programming status while another one on side of the USB port for general access.

1. Connect micro USB cable’s one end to Laptop and other to board’s USB port.
2. Open Arduino IDE and choose board NodeMCU 1.0 from Tools → Boards.
3. Set baud rate to 115200 and choose the port to which it is connected.

4. Copy the code below to IDE.
5. Go to Sketch → Upload
6. Wait for the code to get uploaded. Other blue LED near WiFi chip blinks continuously while the board is being programmed. Don’t confuse it for LED you code will blink.
7. Upon successful completion of the task, IDE will display 100% on the bottom zone and LED will start blinking.

CODE TO BLINK ONBOARD BLUE LED

#define LED D0 //Led in NodeMCU at pin GPIO16 (D0) 

void setup() 
{
 pinMode(LED, OUTPUT); //LED pin as output
}
void loop() 
{
 digitalWrite(LED, HIGH); //turn the led off
 delay(1000); //wait for 1 sec
 digitalWrite(LED, LOW); //turn the led on
 delay(1000); //wait for 1 sec 
}

There’s also a sample program in examples of IDE for blinking onboard LED. To open that, go to File → Examples → ESP8266 → Blink. Open it, upload to board & enjoy or below is the code. Here LED_BUILTIN is used to find the pin with the internal LED.

void setup() 
{
   pinMode(LED_BUILTIN, OUTPUT);    //LED_BUILTIN pin as an output
 }
 void loop() 
{
   digitalWrite(LED_BUILTIN, LOW);   // Turn the LED on
   delay(1000);                      // Wait for a second
   digitalWrite(LED_BUILTIN, HIGH);  // Turn the LED off
   delay(2000);                      // Wait for two seconds
 }

Some Basic Things with NodeMCU ESP8266

Setup Arduino for NodeMCU programming

Blink External LEDs

Interface With Relay (for controlling AC/DC devices)

Get NodeMCU ESP8266 from Amazon India