First Look: APA102 RGB Pixel Addressable LED #2

Part2 of my first look at the APA102 RGB pixel addressable LED

[alpha]

I really appreciated the way that you explained this, including the manual bit banging, it helps bring it all together.

[KeithSalisbury]

Brilliant, just love the depth of your videos!! Thanks

[PanoWorks]

If you look closely near the end, you can see the propagation delay in the string based on the clock. (Takes about 3 video frames).  If I recall correctly, that's one of the other differences with the WS28xx - those you can set the state and then latch in the color display very quickly?  I wonder how fast you can drive the APA102 :)

[jonathanmarino]

Thank you so much for the insight on this LED. I've been scratching my head wondering why the 3 last of my LEDs didn't set correctly. In my case I had to send 12 bytes (or 3 start frames) in order to get them sorted, since I'm running a 144 LED strand. I figure the necessary padding turns out to be (in bytes): 1 + floor(NUM_PIXELS / 16)). In my case it is even necessary to send a byte of padding for the first LED to set.

[RaccoonRocket]

How does the color compare with the neopixels?  Which would you say has a nicer red, green, and blue, and which does better color mixing, ie, can produce a nice saturated yellow?

[JG-gjqe]

thank you very much for your detailed explanation. You should consider being a teacher because it was brought very entertaining. I'm excited about experimenting with these addressable leds and considering implementing them in my house. Thank you for sharing your knowledge!

[jstro-hobbytech]

the 8mm 4 pin dip version of apa106 are the coolest leds I have and I have tens of thousands. they're pricey though. look at the cube someone made with them using a teensy mcu written in assembly. there are 4082 leds and 1000 cost around 120cad haha

you need to make an oscillator/led list. I promise I will hit that thank you button very generously

[chrissing]

I was wondering Julian you have done some really good reviews through your post bag videos on power banks. I'm not really electronically minded, but find your explanations fascinating. I wonder would you be able to do one of your investigations on wireless chargers and explain the different types and how they work please. 

[oreubens]

Have you done actual tests yet how fast you can program the leds...  This makes me wonder... if you'd add a bunch (say 50x100 or so) of them into a rectangular type organisation.  What kind of framerate could you get out of that ?

If you can indeed do it at 60Mhz. That's 1.8Mil LED changes per second.  If you wanted 50Hz framerate, that means you could make a matrix of  37500 LEDs. That's pretty impressive (and way outside of the ballpark for an arduino) .

Or you could make a giant classic VGA 320x200 screen at 29fps.

[Glasshopper]

You make coins more fun than even the super Mario brothers do.

[simonhopkins]

Hi Julian I would appreciate it if you could do a video on the pl9823 f5/ f8 leds.
Thanks Simon.
may the sun always shine in your garden

[jeremyshugert]

Having a end frame would be good if you don't want to fill the whole strip and you are using the same item to give commands to another unit at the same time. not the best use but there if needed. Just an idea

[alexunderwood]

You said there was no set clock speed but is there a cut out time (ie if you sent the start bytes then waited for 30 seconds or so) would it turn off, or not take in any more data bytes?

[icyjones]

Thanks - this was a very helpfull introduction - well done!

[xFuaZe]

Wait, so for bigger strings you'll need a longer "end frame"? How'd that calculation go?

[rupert]

So WS2812B vs APA102; which is better and in what situation?

[nullsmack]

I'm a little confused about why the last LED is special.

[jeremyshugert]

I think it only counts if its your own currency. He is in the UK and thous coins are from Japan so I don't think the UK government would care.

[JanRasmussen]

What struck me is that the end frame coincides with an all white full global frame. If they meant for a serious use of start/end frame, those two should be different from any colour/global intensity frame by differing in the first 3 bits. I.e an end frame could be
Where those i b g & r bits would not matter.
Maybe its all down to the simplicity of the control chip in the LED

[cofjcofj]

It's awesome instruction! Thanks!