ESP32 - NeoPixel LED Strip

The NeoPixel strip is like a strip of colorful RGB LEDs, and you can control each LED's color and brightness on its own. In this guide, we'll discover how to use an ESP32 to control the NeoPixel RGB LED strip. To control all the LEDs on the NeoPixel strip, you only need a single pin on the ESP32.

Hardware Used In This Tutorial

1×ESP-WROOM-32 Dev Module
1×USB Cable Type-C
1×NeoPixel RGB LED Strip
1×1000uF Capacitor
1×470Ω resistor
1×5V Power Adapter
1×(Optional) DC Power Jack
1×Jumper Wires
1×Breadboard
1×(Recommended) Screw Terminal Expansion Board for ESP32

Or you can buy the following sensor kits:

1×DIYables Sensor Kit (30 sensors/displays)
1×DIYables Sensor Kit (18 sensors/displays)
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Introduction to NeoPixel RGB LED Strip

Pinout

The NeoPixel RGB LED strip has three pins:

  • GND pin: needs to be connected to GND (0V)
  • VCC pin: needs to be connected to 5V of external power supply
  • Din pin: is pin that receives the control signal. It should be connected to an ESP32 GPIO pin.
NeoPixel Pinout

Wiring Diagram

ESP32 NeoPixel RGB LED strip Wiring Diagram

This image is created using Fritzing. Click to enlarge image

If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: How to Power ESP32.

How To Program For NeoPixel RGB LED Strip

  • Declare a NeoPixel object
#define PIN_NEO_PIXEL 16 // The ESP32 pin GPIO16 connected to NeoPixel #define NUM_PIXELS 30 // The number of LEDs (pixels) on NeoPixel Adafruit_NeoPixel NeoPixel(NUM_PIXELS, PIN_NEO_PIXEL, NEO_GRB + NEO_KHZ800);
  • Initializes the NeoPixel
NeoPixel.begin(); // INITIALIZE NeoPixel strip object (REQUIRED)
  • Set color of each individual LED (called pixel).
NeoPixel.setPixelColor(pixel, NeoPixel.Color(255, 0, 0));
  • Set brightness of all strip.
NeoPixel.setBrightness(200); // a value from 0 to 255

※ NOTE THAT:

  • NeoPixel.setBrightness() is used for all pixel on LED strip. To set the brightness for each individual pixel, we can scale the color value.
  • The values set by NeoPixel.setBrightness() and NeoPixel.setPixelColor() only take effect when NeoPixel.show() is called.

ESP32 Code

The following code accomplishes the following tasks:

  • It sequentially changes pixels to green, with a pause between each pixel.
  • It turns off all pixels for a duration of two seconds.
  • It simultaneously sets all pixels to red, maintaining this state for 1 second.
  • This entire process is then repeated indefinitely.
/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-neopixel-led-strip */ #include <Adafruit_NeoPixel.h> #define PIN_NEO_PIXEL 16 // The ESP32 pin GPIO16 connected to NeoPixel #define NUM_PIXELS 30 // The number of LEDs (pixels) on NeoPixel LED strip Adafruit_NeoPixel NeoPixel(NUM_PIXELS, PIN_NEO_PIXEL, NEO_GRB + NEO_KHZ800); void setup() { NeoPixel.begin(); // initialize NeoPixel strip object (REQUIRED) } void loop() { NeoPixel.clear(); // set all pixel colors to 'off'. It only takes effect if pixels.show() is called // turn pixels to green one-by-one with delay between each pixel for (int pixel = 0; pixel < NUM_PIXELS; pixel++) { // for each pixel NeoPixel.setPixelColor(pixel, NeoPixel.Color(0, 255, 0)); // it only takes effect if pixels.show() is called NeoPixel.show(); // update to the NeoPixel Led Strip delay(500); // 500ms pause between each pixel } // turn off all pixels for two seconds NeoPixel.clear(); NeoPixel.show(); // update to the NeoPixel Led Strip delay(2000); // 2 seconds off time // turn on all pixels to red at the same time for two seconds for (int pixel = 0; pixel < NUM_PIXELS; pixel++) { // for each pixel NeoPixel.setPixelColor(pixel, NeoPixel.Color(255, 0, 0)); // it only takes effect if pixels.show() is called } NeoPixel.show(); // update to the NeoPixel Led Strip delay(1000); // 1 second on time // turn off all pixels for one seconds NeoPixel.clear(); NeoPixel.show(); // update to the NeoPixel Led Strip delay(1000); // 1 second off time }

Quick Instructions

  • If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
  • Do the wiring as above image.
  • Connect the ESP32 board to your PC via a micro USB cable
  • Open Arduino IDE on your PC.
  • Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
  • Click to the Libraries icon on the left bar of the Arduino IDE.
  • Search “Adafruit NeoPixel”, then find the NeoPixel library by Adafruit
  • Click Install button to install NeoPixel library.
ESP32 NeoPixel library
  • Copy the above code and open with Arduino IDE
  • Click Upload button on Arduino IDE to upload code to ESP32
  • Check out the effect of the LED strip

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