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BG344213471 I found them rather easy to program but you definitely have a point thought because there are some variations of these LEDs that looks identical at a first glance but they've got slightly different timings and they're kind of tight on your average MCU so make sure you get the right datasheet. They're so-so but for an engrish datasheet and the simplicity of the protocol they're good enough, if they bother to actually mention which model it applies to. Having read through the timings for different models there is a common timing scheme that seems to work on most devices. The reset time varies and is not very accurate in regards to actual use (they might say 50 ms when 8 ms is plenty, or maybe it was micros but regardless... it's a bit of trial and error of you're writing your own code but it's not that time consuming, just a few tweaks here and there and they'll happily cause temporary blindness if you're not aware of how bright these things can be).

DrMichael 12/08/2022
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BG344213471 Thanks for the detailed review. I've 50 of these on the way for a project or two. I have the 64 (8x8) WS2812B 5050 matrix, wrote my own AVR code for it to make work because I wanted to (surprisingly easy to program) and my burned eyebrows confirms that my code is indeed working. Man these things are bright! Question. Do these things get dimmer at 3.3V vs 5V? I can't really tell the difference in brightness after about 50% (128,128,128) and (255,255,255) appear pretty similar. The other thing is gamma, but I'm guessing at least Adafruit has some features to handle this. Do you use gamma tables for more accurate color mixing? One table for each primary or one common table (sacrifices some accuracy given how green is a lot brighter than the other two, and there's also a difference between red and blue but not as extreme). Do you use the whole range or reduce it to a predefined gamma corrected 16 or 256 color palette? I mean if you've played around with it to that extent that is. I guess most people just want it to work and use existing libraries to get things going, but since I'm a curious idiot I run into things like this so ... any feedback from you or anyone else always appreciated. Thanks! Have fun!

Neo2121 02/06/2016
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Q: does this come with a users manual?

gefragt von james auf 2017-11-13 12:13:08

BG344213471 Depends on what you mean by "users manual". The datasheet for the MAX7219 controller is excellent and all you need to know to program these things. If you want plug and play there are multiple libraries to choose from.

2022-08-31 02:16:09 Hilfreich (0)
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BG344213471 Yes. Remember, there are already 4 of these ICs chained together. The PCB comes with connections for further chaining, but as mentioned you probably need to inject some extra power.

2022-08-31 02:13:36 Hilfreich (0)
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Q: what colors are possible?

gefragt von KATOK auf 2017-12-25 10:43:26

BG344213471 @BG495298131 look it up in the MAX7219 datasheet. Another cool thing about these ICs is the need for just one resistor to limit the current for all segments x digits (64 per IC) to retain the same brightness whether only one LED is on or all 64. IIRC there's a chart there with recommended resistor values depending on number of LEDs. I could probably lift one of the 8x8 matrices off and see what resistor value they've used, but the datasheet should give you an idea. Assume you need an external power supply though. They're not super bright but it's still 256 LEDs.

2022-08-31 02:08:01 Hilfreich (0)
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