For a project my team is making bike turn signals and we wanted to us an addressable LED strip for the indicators. We purchased this strip:
We downloaded the Adafruit libraries, ran testers and examples, watched countless videos but we cannot seem to properly get the LEDs to light. We are using a 5v external power supply with a 1000microFarad capacitor connected directly to the strip. The DIN lead is connected via 330ohm resistor to the UNO board that is powered with the USB input from the computer (is this a problem?).
This youtube video (Easy Addressable LEDs with Arduino! WS2812B Tutorial - YouTube) was what we felt came the closest to working, though we could be wrong. The code from the video is:
#define WS2812_pin 8 // only digital pin 8 works right now
#define numberOfLEDs 150// total number of RGB LEDs
byte RGB[450];//take your number of LEDs and multiply by 3
// FUNCTIONS HERE
void RGB_update(int LED, byte RED, byte GREEN, byte BLUE);//function to drive LEDs
void setup() {
pinMode(WS2812_pin, OUTPUT);
}//setup
void loop() {
RGB_update(0,0,0,0);//LED#, RED, GREEN, BLUE
delay(1000);
}//loop
//WS2812 Driver Function
void RGB_update(int LED, byte RED, byte GREEN, byte BLUE) {
// LED is the LED number starting with 0
// RED, GREEN, BLUE is the brightness 0..255 setpoint for that LED
byte ExistingPort, WS2812pinHIGH;//local variables here to speed up pinWrites
if(LED>=0){//map the REG GREEN BLUE Values into the RGB[] array
RGB[LED * 3] = GREEN;
RGB[LED * 3 + 1] = RED;
RGB[LED * 3 + 2] = BLUE;
}
noInterrupts();//kill the interrupts while we send the bit stream out...
ExistingPort = PORTB; // save the status of the entire PORT B - let's us write to the entire port without messing up the other pins on that port
WS2812pinHIGH = PORTB | 1; //this gives us a byte we can use to set the whole PORTB with the WS2812 pin HIGH
int bitStream = numberOfLEDs * 3;//total bytes in the LED string
//This for loop runs through all of the bits (8 at a time) to set the WS2812 pin ON/OFF times
for (int i = 0; i < bitStream; i++) {
PORTB = WS2812pinHIGH;//bit 7 first, set the pin HIGH - it always goes high regardless of a 0/1
//here's the tricky part, check if the bit in the byte is high/low then right that status to the pin
// (RGB[i] & B10000000) will strip away the other bits in RGB[i], so here we'll be left with B10000000 or B00000000
// then it's easy to check if the bit is high or low by AND'ing that with the bit mask ""&& B10000000)"" this gives 1 or 0
// if it's a 1, we'll OR that with the Existing port, thus keeping the pin HIGH, if 0 the pin is written LOW
PORTB = ((RGB[i] & B10000000) && B10000000) | ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");//these are NOPS - these let us delay clock cycles for more precise timing
PORTB = ExistingPort;//okay, here we know we have to be LOW regardless of the 0/1 bit state
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");//minimum LOW time for pin regardless of 0/1 bit state
// then do it again for the next bit and so on... see the last bit though for a slight change
PORTB = WS2812pinHIGH;//bit 6
PORTB = ((RGB[i] & B01000000) && B01000000) | ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = WS2812pinHIGH;//bit 5
PORTB = ((RGB[i] & B00100000) && B00100000) | ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = WS2812pinHIGH;//bit 4
PORTB = ((RGB[i] & B00010000) && B00010000) | ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = WS2812pinHIGH;//bit 3
PORTB = ((RGB[i] & B00001000) && B00001000) | ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = WS2812pinHIGH;//bit 2
PORTB = ((RGB[i] & B00000100) && B00000100) | ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = WS2812pinHIGH;//bit 1
PORTB = ((RGB[i] & B00000010) && B00000010) | ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = WS2812pinHIGH;//bit 0
__asm__("nop\n\t");//on this last bit, the check is much faster, so had to add a NOP here
PORTB = ((RGB[i] & B00000001) && B00000001) | ExistingPort;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
PORTB = ExistingPort;//note there are no NOPs after writing the pin LOW, this is because the FOR Loop uses clock cycles that we can use instead of the NOPS
}//for loop
interrupts();//enable the interrupts
// all done!
}//void RGB_update
We purchased two different strips with the same WS2812B IC's and the LEDs do occasionally flash when connected to power so we do not think that the strips are to blame.
Any help in getting the strips lit would be greatly, greatly appreciated!