ESP32 - Dotstar LED Strip

In this tutorial, we are going to learn how to use ESP32 to control DotStar RGB LED strip. In detail, we will learn:

Hardware Used In This Tutorial

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

Or you can buy the following sensor kit:

1×DIYables Sensor Kit 30 types, 69 units
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Introduction to DotStar RGB LED Strip

Pinout

the DotStar RGB LED Strip has three pins:

  • GND pin: needs to be connected to GND (0V)
  • CI pin: Clock pin that receives the clock signal. It should be connected to an ESP32 pin.
  • DI pin: Data pin that receives the control signal. It should be connected to an ESP32 pin.
  • 5V pin: needs to be connected to 5V of external power supply
DotStar Pinout

Wiring Diagram

ESP32 DotStar 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 DotStar RGB LED Strip

  • Include a DotStar library
#include <Adafruit_DotStar.h> #include <SPI.h> // COMMENT OUT THIS LINE FOR GEMMA OR TRINKET
  • Declare a DotStar object
#define NUMPIXELS 144 // Number of LEDs in strip // Here's how to control the LEDs from any two pins: #define DATAPIN 16 #define CLOCKPIN 17 Adafruit_DotStar strip(NUMPIXELS, DATAPIN, CLOCKPIN, DOTSTAR_BRG);
  • Initializes the DotStar
strip.begin(); // Initialize pins for output strip.setBrightness(255); strip.show(); // Turn all LEDs off ASAP
  • Set color (r. g, b) of each individual LED (called pixel) .
strip.setPixelColor(pixel, g, r, b);
  • Set brightness of all strip.
strip.setBrightness(100); // a value from 0 to 255

※ NOTE THAT:

  • DotStar.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 DotStar.setBrightness() and DotStar.setPixelColor() only take effect when DotStar.show() is called.

ESP32 Code

The below code turns pixels to red one by one with a delay between each pixel

/* * 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-dotstar-led-strip */ #include <Adafruit_DotStar.h> #include <SPI.h> // COMMENT OUT THIS LINE FOR GEMMA OR TRINKET #define NUMPIXELS 144 // Number of LEDs in strip // Here's how to control the LEDs from any two pins: #define DATAPIN 16 // The ESP32 pin GPIO16 #define CLOCKPIN 17 // The ESP32 pin GPIO17 Adafruit_DotStar strip(NUMPIXELS, DATAPIN, CLOCKPIN, DOTSTAR_BRG); void setup() { Serial.begin(9600); strip.begin(); // INITIALIZE NeoPixel strip object (REQUIRED) strip.show(); // Turn OFF all pixels ASAP strip.setBrightness(255); } void loop() { for (int pixel = 0; pixel < NUMPIXELS; pixel++) { // red color int r = 255; // CHANGE COLOR AS YOUR DESIRE int g = 0; // CHANGE COLOR AS YOUR DESIRE int b = 0; // CHANGE COLOR AS YOUR DESIRE strip.clear(); // turn off all pixel strip.setPixelColor(pixel, g, r, b); // turn on a single pixel strip.show(); delay(1000); // keep each pixel on 1 seconds } }

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 DotStar”, then find the DotStar library by Adafruit
  • Click Install button to install DotStar library.
ESP32 DotStar library
  • You will be asked to install the dependency. Click Install All button.
ESP32 keypad library
  • Copy the above code and open with Arduino IDE
  • Click Upload button on Arduino IDE to upload code to ESP32
  • See the LED effect

ESP32 Code - LED Strip Comet Effect

The below code provides the comet effect for the DotStar LED strip

/* * 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-dotstar-led-strip */ #include <Adafruit_DotStar.h> #include <SPI.h> // COMMENT OUT THIS LINE FOR GEMMA OR TRINKET #define COMET_LENGTH_ALL 30 // in pixel COMET_LENGTH_ALL = COMET_LENGTH_BODY + COMET_LENGTH_HEAD #define COMET_LENGTH_BODY 25 // in pixel #define COMET_LENGTH_HEAD 5 // in pixel #define TWO_COMET_DISTANCE 10 // in pixel #define COMET_SPEED 2000 // in millisecond, the time need to move through 144 pixels #define COMET_COLOR_R 204 // color #define COMET_COLOR_G 255 // color #define COMET_COLOR_B 255 // color #define COMET_BRIGHTNESS_MIN 1 #define COMET_BRIGHTNESS_MAX 200 #define COMET_BRIGHTNESS_HEAD 80 #define FLICKER_MAX 255 #define FLICKER_MIN 100 #define FLICKER_SPEED 800 // in millisecond #define NUMPIXELS 144 // Number of LEDs in strip // Here's how to control the LEDs from any two pins: #define DATAPIN 16 // The ESP32 pin GPIO16 #define CLOCKPIN 17 // The ESP32 pin GPIO17 Adafruit_DotStar strip(NUMPIXELS, DATAPIN, CLOCKPIN, DOTSTAR_BRG); int pos_head = 0; unsigned long cometTimeStart; unsigned long flickerTimeStart; unsigned long progress; unsigned long cometBrightness; unsigned long flickerBrightness; unsigned long TIME_PER_PIXEL; void setup() { Serial.begin(9600); strip.begin(); // INITIALIZE NeoPixel strip object (REQUIRED) strip.show(); // Turn OFF all pixels ASAP strip.setBrightness(255); TIME_PER_PIXEL = map(1, 0, NUMPIXELS, 0, COMET_SPEED); cometTimeStart = millis(); flickerTimeStart = millis(); } void loop() { progress = millis() - flickerTimeStart; if (progress >= 2 * FLICKER_SPEED) { progress = 2 * FLICKER_SPEED; flickerTimeStart = millis(); } if (progress > FLICKER_SPEED) progress = 2 * FLICKER_SPEED - progress; flickerBrightness = map(progress, 0, FLICKER_SPEED, FLICKER_MIN, FLICKER_MAX); strip.setBrightness(flickerBrightness); progress = millis() - cometTimeStart; if (progress >= TIME_PER_PIXEL) { pos_head++; pos_head %= (COMET_LENGTH_ALL + TWO_COMET_DISTANCE); int offset = COMET_LENGTH_ALL - pos_head; for (int pixel = 0; pixel < NUMPIXELS; pixel++) { int pos_offset = pixel + offset; pos_offset %= (COMET_LENGTH_ALL + TWO_COMET_DISTANCE); if (pos_offset < COMET_LENGTH_BODY) cometBrightness = map(pos_offset, 0, COMET_LENGTH_BODY - 1, COMET_BRIGHTNESS_MIN, COMET_BRIGHTNESS_MAX); else if (pos_offset >= COMET_LENGTH_BODY && pos_offset < COMET_LENGTH_ALL) cometBrightness = map(pos_offset - COMET_LENGTH_BODY + 1, 0, COMET_LENGTH_ALL - COMET_LENGTH_BODY, COMET_BRIGHTNESS_MAX, COMET_BRIGHTNESS_HEAD); else cometBrightness = 0; int r = (COMET_COLOR_R * cometBrightness) >> 8; int g = (COMET_COLOR_G * cometBrightness) >> 8; int b = (COMET_COLOR_B * cometBrightness) >> 8; strip.setPixelColor(pixel, g, r, b); } strip.show(); cometTimeStart = millis(); // new circle } }

※ NOTE THAT:

For any other LED effects, we offer the paid programming service

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