Arduino keeps crashing - arduino

Question

I've got an Arduino with a WS2812 hooked up to it, powered by the USB on my computer and I am trying to run the following code:
#include <FastLED.h>
#define NUM_LEDS 144
#define DATA_PIN 6
#define LED_TYPE WS2812B
#define COLOR_ORDER GRB
CRGB leds[NUM_LEDS];
void setup() {
FastLED.addLeds<LED_TYPE, DATA_PIN, COLOR_ORDER>(leds, NUM_LEDS);
FastLED.show();
}
void loop() {
for(int dot = 0; dot < NUM_LEDS; dot++) {
fill_solid(leds, NUM_LEDS, CRGB::Red);
leds[dot] = CRGB::Black;
leds[dot] = CRGB::Blue;
FastLED.show();
leds[dot] = CRGB::Red;
delay(30);
}
}
void setAll() {
FastLED.show();
}
What this does is sets all the LEDs to red, then goes through each one turning it off, then to blue and then back to red.
For some reason, it gets X number of LEDs along and then crashes. By crashes I mean the Arduino disconnects itself from the computer, but the Arduino stays on with the LED strip still powered up.
Any ideas? This is a genuine Uno.
Also. If I plug the LED into the 3.3v pin, the animations works just fine, but the LED flashes black and doesn't complete the Blue part.

Answer 1

I never used the NeoPixels, so I'm not really sure about this, but I'm pretty confident these will solve your problem.
First of all, your program. I don't think it is doing what you think it should do. Try with this loop, instead:
void loop()
{
fill_solid(leds, NUM_LEDS, CRGB::Red);
FastLED.show();
delay(100);
for(int dot = 0; dot < NUM_LEDS; dot++)
{
leds[dot] = CRGB::Black;
FastLED.show();
delay(100);
leds[dot] = CRGB::Blue;
FastLED.show();
delay(100);
leds[dot] = CRGB::Red;
FastLED.show();
delay(100);
}
}
and remove the SetAll function, since it is useless.
Try this code with NUM_LEDS set to 5, and it should work.
Now the main problem: are you really using 144 leds powered by the USB? I suggest you to read this link about powering the neopixels. Particularly the part stating that at full brightness each neopixel draws 60mA. Doing the math, 144 neopixels draw at most 8.64A, so you need a 5V 10A power supply to power them all! a USB with 5V 0.5A will just shut itself down when you try to turn them on, thus giving you strange behaviors.
So lower the number of leds you are using (7 at most), or use an external power supply. And by external I do not mean use the barrel jack on the arduino, but connect a 5V 10A (or more amps) to the neopixel strip, then the ground and data wire to the arduino (not the +5v) and power the arduino through the usb port: it should work.
UPDATE:
According to the chat with the author, the problem was indeed the power supply

Answer 2

The datasheet from adafruit https://cdn-shop.adafruit.com/datasheets/WS2812.pdf says that you need a power supply between 6v and 7v but USB cannot provide more than 5v, I am guessing the arduino crashes because it cannot find enough power.
Can you try using an external power supply?