SENSORS/ACTUATORS

ESP8266 - Blink multiple LED

This tutorial instructs you how to program the ESP8266 to blink multiple LEDs simultaneously, each blinking at a different frequency, without relying on the delay function. We'll use three LEDs as an example, but you can adjust the code to handle more LEDs easily.

Hardware Preparation

1	×	ESP8266 NodeMCU
1	×	Micro USB Cable
1	×	LED
1	×	220 ohm resistor
1	×	Breadboard
1	×	Jumper Wires
1	×	(Optional) DC Power Jack
1	×	(Optional) ESP8266 Screw Terminal Adapter

Or you can buy the following sensor kit:

DIYables Sensor Kit 30 types, 69 units

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Overview of LED

We have specific a tutorial about LED. The tutorial contains detailed information and step-by-step instructions about hardware pinout, working principle, wiring connection to ESP8266, ESP8266 code... Learn more about them at the following link:

ESP8266 - LED tutorial

Wiring Diagram

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See more in ESP8266's pinout and how to supply power to the ESP8266 and other components.

ESP8266 Code - Blink Multiple LEDs

To blink multiple LEDs, we cannot use the delay() function. Instead, we need to use the millis() function and manage the timestamps .

Managing timestamps while blinking multiple LEDs can be challenging for beginners. Thankfully, the ezLED library simplifies the process of blinking multiple LEDs by internally managing timestamps. This eliminates the need for users to handle timestamp management when utilizing this library. Additionally, you can enhance code clarity and brevity by employing an array of LEDs.

/* * This ESP8266 NodeMCU code was developed by newbiely.com * * This ESP8266 NodeMCU code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/esp8266/esp8266-blink-multiple-led */ #include <ezLED.h> // ezLED library #define PIN_LED_1 D5 // The ESP8266 pin connected to LED 1 #define PIN_LED_2 D6 // The ESP8266 pin connected to LED 2 #define PIN_LED_3 D7 // The ESP8266 pin connected to LED 3 ezLED led1(PIN_LED_1); // create ezLED object that attach to pin PIN_LED_1 ezLED led2(PIN_LED_2); // create ezLED object that attach to pin PIN_LED_2 ezLED led3(PIN_LED_3); // create ezLED object that attach to pin PIN_LED_3 void setup() { Serial.begin(9600); led1.blink(500, 500); // 500ms ON, 500ms OFF, blink immediately led2.blink(200, 800); // 200ms ON, 800ms OFF, blink immediately led3.blink(200, 200); // 200ms ON, 200ms OFF, blink immediately } void loop() { led1.loop(); // MUST call the led1.loop() function in loop() led2.loop(); // MUST call the led2.loop() function in loop() led3.loop(); // MUST call the led3.loop() function in loop() // DO SOMETHING HERE }

Detailed Instructions

To get started with ESP8266 on Arduino IDE, follow these steps:

Check out the how to setup environment for ESP8266 on Arduino IDE tutorial if this is your first time using ESP8266.
Wire the components according to the provided diagram.
Connect the ESP8266 board to your computer using a USB cable.
Launch the Arduino IDE on your computer.
Select the ESP8266) board and its corresponding COM port.
Click to the Libraries icon on the left bar of the Arduino IDE.
Search “ezLED”, then find the led library by ArduinoGetStarted
Click Install button to install ezLED library.

Copy the above code and paste it to Arduino IDE.
Compile and upload code to ESP8266 board by clicking Upload button on Arduino IDE

How to upload ESP8266 NodeMCU code on Arduino IDE

Check out the status of LED

ESP8266 Code - Blink Multiple LEDs by using array

We can optimize the above code by using an array of LEDs. The below code uses the array to manage LED objects.

/* * This ESP8266 NodeMCU code was developed by newbiely.com * * This ESP8266 NodeMCU code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/esp8266/esp8266-blink-multiple-led */ #include <ezLED.h> // ezLED library #define NUM_LED 3 // three LEDs #define PIN_LED_1 D5 // The ESP8266 pin connected to LED 1 #define PIN_LED_2 D6 // The ESP8266 pin connected to LED 2 #define PIN_LED_3 D7 // The ESP8266 pin connected to LED 3 ezLED ledArray[NUM_LED] = { ezLED(PIN_LED_1), // create ezLED object that attach to pin PIN_LED_1 ezLED(PIN_LED_2), // create ezLED object that attach to pin PIN_LED_2 ezLED(PIN_LED_3) // create ezLED object that attach to pin PIN_LED_3 }; void setup() { Serial.begin(9600); ledArray[0].blink(500, 500); // 500ms ON, 500ms OFF, blink immediately ledArray[1].blink(200, 800); // 200ms ON, 800ms OFF, blink immediately ledArray[2].blink(200, 200); // 200ms ON, 200ms OFF, blink immediately } void loop() { for (int i = 0; i < NUM_LED; i++) ledArray[i].loop(); // MUST call the led.loop() function in loop() // DO SOMETHING HERE }

For the flexible blink, please refer to other functions of the ezLED library

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