SENSORS/ACTUATORS

Arduino Nano 33 IoT - Blink multiple LED

This guide shows you how to set up the Arduino Nano 33 IoT to make several LEDs blink at the same time without using the delay function. Each LED can blink at its own speed. We use three LEDs as an example, but you can easily change the code to use more LEDs.

Hardware Preparation

1	×	Arduino Nano 33 IoT
1	×	Micro USB Cable
1	×	LED Kit with resistor
1	×	LED (red)
1	×	220 ohm resistor
1	×	Breadboard
1	×	Jumper Wires
1	×	Optionally, DC Power Jack
1	×	Recommended: Screw Terminal Expansion Board for Arduino Nano
1	×	Recommended: Breakout Expansion Board for Arduino Nano
1	×	Recommended: Power Splitter for Arduino Nano

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables .

Overview of LED

We have a tutorial about LEDs. This guide gives clear, simple steps on how the LED works, explains the hardware pins, shows how to connect it to an Arduino Nano 33 IoT, and includes the code for it. Learn more at the following link:

Arduino Nano 33 IoT - LED tutorial

Wiring Diagram

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Arduino Nano 33 IoT Code - Blink Multiple LEDs

To make many LEDs blink at once, we can't use the delay() function. Instead, we need to use the millis() function and keep track of the time.

Handling time records while blinking many LEDs can be hard for beginners. Fortunately, the ezLED library makes things easier because it manages the time records for you. You don't have to worry about it yourself. Also, you can make your code clearer and shorter by using an array of LEDs.

/* * This Arduino Nano 33 IoT code was developed by newbiely.com * * This Arduino Nano 33 IoT code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano-iot/arduino-nano-33-iot-blink-multiple-led */ #include <ezLED.h> // ezLED library #define PIN_LED_1 4 // The Arduino Nano 33 IoT pin connected to LED 1 #define PIN_LED_2 5 // The Arduino Nano 33 IoT pin connected to LED 2 #define PIN_LED_3 6 // The Arduino Nano 33 IoT 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

If you are new to the Arduino Nano 33 IoT, be sure to check out our Getting Started with Arduino Nano 33 IoT tutorial. Then, follow these steps:

Connect the components to the Arduino Nano 33 IoT board as depicted in the diagram.
Use a USB cable to connect the Arduino Nano 33 IoT board to your computer.
Launch the Arduino IDE on your computer.
Select the Arduino Nano 33 IoT board and choose its corresponding COM port.
Click on the Libraries icon on the left side of the Arduino IDE.
Type ezLED in the search box and find the LED library by ArduinoGetStarted.
Click the Install button to add the ezLED library.

Copy the code above and paste it into the Arduino IDE. Then click the Upload button to compile and send the code to the Arduino Nano 33 IoT board.

How to upload Arduino Nano 33 IoT code on Arduino IDE

Look to see if the LED light is working.

Arduino Nano 33 IoT Code - Blink Multiple LEDs by using array

We can improve the previous code by using an array of LEDs. The code below uses this array to control the LED objects.

/* * This Arduino Nano 33 IoT code was developed by newbiely.com * * This Arduino Nano 33 IoT code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano-iot/arduino-nano-33-iot-blink-multiple-led */ #include <ezLED.h> // ezLED library #define NUM_LED 3 // three LEDs #define PIN_LED_1 4 // The Arduino Nano 33 IoT pin connected to LED 1 #define PIN_LED_2 5 // The Arduino Nano 33 IoT pin connected to LED 2 #define PIN_LED_3 6 // The Arduino Nano 33 IoT 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 flexible blinking, please check out the other functions in the ezLED library.

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