I'm having a little trouble understanding HEX values (because of my nativity with HEX) for colors and working with an Adafruit Neopixel Stick 8. My processor is an ESP32. I'm just testing the first Neopixel on the stick.
I've written a little sketch to check the color order of the Neopixels which I seem to have correct with NEO_GRB.
The first part of the loop correctly lights the Neopixel in order of R,G,B per the for loop to advance the Hex value.
The Second part of the Main loop uses predefined HEX color values to sequence thru R,G, B and DOES NOT work correctly but rather sequences: G,B,B. Here is the Serial printout:
FF0000
FF00
FF
F800
7E0
1F
What am I missing, or need to understand about HEX color value? My understanding is that, for instance, RED is FF0000 not F800?
Thanks for your patience in advance.
Mark
// A basic sketch to test color order for NeoPixels
// NEOPIXEL BEST PRACTICES for most reliable operation:
// - Add 1000 uF CAPACITOR between NeoPixel strip's + and - connections.
// - MINIMIZE WIRING LENGTH between microcontroller board and first pixel.
// - NeoPixel strip's DATA-IN should pass through a 300-500 OHM RESISTOR.
// - AVOID connecting NeoPixels on a LIVE CIRCUIT. If you must, ALWAYS
// connect GROUND (-) first, then +, then data.
// - When using a 3.3V microcontroller with a 5V-powered NeoPixel strip,
// a LOGIC-LEVEL CONVERTER on the data line is STRONGLY RECOMMENDED.
// (Skipping these may work OK on your workbench but can fail in the field)
#include <Adafruit_NeoPixel.h>
#ifdef __AVR__
#include <avr/power.h> // Required for 16 MHz Adafruit Trinket
#endif
// Which pin on the Arduino is connected to the NeoPixels?
// On a Trinket or Gemma we suggest changing this to 1:
#define LED_PIN DAC2
// How many NeoPixels are attached to the Arduino?
#define LED_COUNT 1
// Declare our NeoPixel strip object:
Adafruit_NeoPixel strip(LED_COUNT, LED_PIN, NEO_GRB + NEO_KHZ800);
// Argument 1 = Number of pixels in NeoPixel strip
// Argument 2 = Arduino pin number (most are valid)
// Argument 3 = Pixel type flags, add together as needed:
// NEO_KHZ800 800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)
// NEO_KHZ400 400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)
// NEO_GRB Pixels are wired for GRB bitstream (most NeoPixel products)
// NEO_RGB Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)
// NEO_RGBW Pixels are wired for RGBW bitstream (NeoPixel RGBW products)
// setup() function -- runs once at startup --------------------------------
void setup() {
Serial.begin(115200);
// These lines are specifically to support the Adafruit Trinket 5V 16 MHz.
// Any other board, you can remove this part (but no harm leaving it):
#if defined(__AVR_ATtiny85__) && (F_CPU == 16000000)
clock_prescale_set(clock_div_1);
#endif
// END of Trinket-specific code.
strip.begin(); // INITIALIZE NeoPixel strip object (REQUIRED)
strip.show(); // Turn OFF all pixels ASAP
strip.setBrightness(150); // Set BRIGHTNESS to about 1/5 (max = 255)
}
static const uint16_t ORANGE = 0xFD20;
static const uint16_t PINK = 0xF81F;
static const uint16_t RED = 0xF800;
static const uint16_t GREEN = 0x07E0;
static const uint16_t BLUE = 0x001F;
static const uint16_t CYAN = 0x07FF;
static const uint16_t MAGENTA = 0xF81F;
static const uint16_t YELLOW = 0xFFE0;
static const uint16_t BLACK = 0x0000;
// loop() function -- runs repeatedly as long as board is on ---------------
void loop() {
for (uint32_t color = 0xFF0000; color > 0; color >>= 8) { // test correct color order
strip.setPixelColor(0, color);
Serial.println(color, HEX);
strip.show();
delay(1000);
}
strip.clear();
strip.show();
delay(1000);
Serial.println();
strip.setPixelColor(0, RED);
strip.show();
Serial.println(RED, HEX);
delay(1000);
strip.clear();
strip.show();
delay(1000);
strip.setPixelColor(0, GREEN);
strip.show();
Serial.println(GREEN, HEX);
delay(1000);
strip.clear();
strip.show();
delay(1000);
strip.setPixelColor(0, BLUE);
strip.show();
Serial.println(BLUE, HEX);
delay(1000);
strip.clear();
strip.show();
Serial.println();
delay(2000);
}
