Hi group,
This post is meant as a reference for projects using white-only APA102 strips.
The following information took me a while to find across the web so here it is now that I have received my strip and tested it.
leds[n].setRGB(0,0,0) // off
leds[n] = CRGB::Black ) //off
leds[n].setRGB(255,255,255) //full brightness
leds[n] = CRGB::White ) //full brightness
leds[n].setRGB(127,127,127) //medium brightness. Technically 50% but not perceptibly 50%. Refer to dimming function for further reading.
What you need to know is that there are physically 3 LEDs per die (unit of strip).
leds[n].setRGB(127,0,0) //medium brightness
leds[n].setRGB(0,127,0) //medium brightness
leds[n].setRGB(0,0,127) //medium brightness
These three look the same but I cannot measure if they are exactly equal (should give the same intensity). If you loop leds[0] between the three settings, you see a different quadrant light up on the die of leds[0].
Now, what this implies is that you have more than 1 byte of brightness control (resolution between steps). For example :
0,0,127 < 0,127,127 < 127,127,127
That said, I am not sure how the brightness maps and I can’t predict complicated cases… For example: 0,0,255 versus 127,0,127…
About the LED strip I used:
5m strip, cold white, IP30, 72 LED/meter
6 weeks between order and receipt of goods in Montreal, Canada
All the LED’s work.
Average power draw @ full brightness: 50.5 mW
55.8 mW for 1 unit
104.2 mW for 2 units
151.4 mW for 3 units
Supplier Greenglow on Aliexpress: https://www.aliexpress.com/item/5mX-High-quality-APA102-5050SMD-white-color-addressable-led-strip-32-60-72-144LED-m-White/32451954771.html?spm=a2g0s.9042311.0.0.3da24c4d1wjYHd
example video: https://youtu.be/iSPEHsRzaO8