user48948: The APA106 RGB LED is usually blue when 5VDC is applied. Sometimes it is a random color when turning the power supply on and off. How to keep it a consistent color when power is applied? 
Normal:

Sometimes:

It’s for an Arduino project, I’ve just isolated the problem to the LED. Dozens of these exhibit this behaviour. The PCB board in the pictures is just a breadboard power supply. 
Update: DIN to GND still exhibits the same behaviour. 

Here is a demo of the problem. 90% of the time at power up the LEDs is blue, but occasionally the color is random like pink or white. 
YouTube link to a 38s clip of the problem manifesting
Update: At Robert's suggestion, I modified the V-USB bootloader to send the control bits and timings to immediately turn off the APA106 LED. There is still an extremely brief blue pulse (or random color) because power applied to the LED is always faster than any CPU process. It's not perfect, but better.

user313: Wire it to the MCU such that power is first applied to the LED under control of the sketch when the sketch is prepared to immediately set the initial color you want. The time taken to accomplish the (power up, set initial color) will have to be less than the eye's ability to perceive the possible color glitch (which, being relatively slow compared to the Arduino, it should be pretty easy to do).
Update:

There is still an extremely brief blue pulse

That remaining delay is probably the IDE's reset-pulse duration plus the Arduino board's R-C delay on the reset pin. It's probably the best you can do without a lot of hardware (e.g. a switch on every R/G/B pin, designed to power-up "off".)

48948: <p>The APA106 RGB LED is usually blue when 5VDC is applied. Sometimes it is a random color when turning the power supply on and off. How to keep it a consistent color when power is applied? </p>

<p>Normal:
<a href="https://i.stack.imgur.com/QdAEk.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QdAEk.jpg" alt="normal blue apa106"></a></p>

<p>Sometimes:
<a href="https://i.stack.imgur.com/xc1SO.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/xc1SO.jpg" alt="sometimes random color apa106"></a></p>

<p>It’s for an Arduino project, I’ve just isolated the problem to the LED. Dozens of these exhibit this behaviour. The PCB board in the pictures is just a breadboard power supply. </p>

<p><strong>Update:</strong> DIN to GND still exhibits the same behaviour. </p>

<p><a href="https://i.stack.imgur.com/gtHiQ.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gtHiQ.jpg" alt="din to gnd still pink"></a></p>

<p>Here is a demo of the problem. 90% of the time at power up the LEDs is blue, but occasionally the color is random like pink or white. </p>

<p><a href="https://youtu.be/bITeGnsc7T8" rel="nofollow noreferrer">YouTube link to a 38s clip of the problem manifesting</a></p>

<p><strong>Update:</strong> At Robert's suggestion, I modified the V-USB <a href="https://github.com/ericdraken/micronucleus" rel="nofollow noreferrer">bootloader</a> to send the control bits and timings to immediately turn off the APA106 LED. There is still an extremely brief blue pulse (or random color) because power applied to the LED is always faster than any CPU process. It's not perfect, but better.</p>
 313: <p>Wire it to the MCU such that power is first applied to the LED under control of the sketch when the sketch is prepared to immediately set the initial color you want. The time taken to accomplish the (power up, set initial color) will have to be less than the eye's ability to perceive the possible color glitch (which, being relatively slow compared to the Arduino, it should be pretty easy to do).</p>

<p>Update:</p>

<blockquote>
  <p>There is still an extremely brief blue pulse</p>
</blockquote>

<p>That remaining delay is probably the IDE's reset-pulse duration plus the Arduino board's R-C delay on the reset pin. It's probably the best you can do without a lot of hardware (e.g. a switch on every R/G/B pin, designed to power-up "off".)</p>
