NLED Project Design Guide - Pixels
Smart or Addressable Pixels:
The most important part of a LED project, the LED didoes.
Smart or Addressable Pixels: The most recent development in LEDs, these usually contain integrated RGB or RGBW LED diodes with an integrated driver. The pixels are not powered by the controller but rather receive a digital data signal that the pixel uses to output variable light intensities. Multiple pixels can be (daisy) chained together one after the other to create strands of pixels. Each pixel in the strand can be individually controlled through the data protocol. Pixels come in different chipsets, each chipset requires a different data protocol and has different features and capabilities. Look online for additional information. And visit the LED Pixel Chipsets page for supported chipsets supported by NLED.
Pixel Chipsets: Pixels are built around what is called a 'chipset', that is the integrated circuit that does the protocol decoding, current regulation, and PWM output. They are available in multiple form factors, capabilities, colors(RGB, RGB-WW, RGB-CW) all with different with pros and cons.
https://www.nledshop.com/pixelchipsets/
https://github.com/FastLED/FastLED/wiki/Chipset-reference
https://www.didel.com/RGBstrips.pdf
Chipset Protocol: Each chipset uses a different protocol, which can be considered similar to a spoken language. The controller must 'speak' the same language as the chipset understands. Some protocols are similar to others and can be used interchangeably, and some protocols are standardized and is supported by multiple chipsets.
Chipset PWM: An important, if not most important characteristic of a chipset. PWM frequency and PWM resolution. Described on the NLED chipsets webpage and on external links.
https://www.arduino.cc/en/Tutorial/SecretsOfArduinoPWM
https://en.wikipedia.org/wiki/Pulse-width_modulation
Chipset, Asynchronous vs Synchronous: Describes how many 'wires' it takes to control a pixel. Synchronous uses protocols similar to SPI that uses a wire for clock and data. These are typically much faster to transmit data to and easier to write the code routines. Asynchronous use a single wire(DAT) to send the data, it is time based and has to be transmitted with the exact timings. Can be very difficult to build and transmit the required data, but is easy to wire and typically the cheapest option.
5050 Pixel: The most popular chipset of WS2812 has all the electronics integrated into a single '5050' RGB LED. The '5050' form factor is 5mm x 5mm and is an industry standard size, and there are more sizes being sold, such as the APA102-2020 which is 2mm x 2mm. Other chipsets such as the APA102 also are an integrated 5050, but has more pins as it is synchronous.
Pixel Module: Chipsets like the WS2811, may be on a strip with 5050 LEDs, but can be considered a module, as the WS2811 typically will control groups of 3 LEDs(per section), each LED is not individually controllable. Some pixel modules are separate modules with 3 or more LEDs per module, each module is individually controllable, but not per LED. They are connected together in a strand with ribbon cable between them. Common example are WS2801 or WS2811 based 12 volt modules with 3x or 6x 5050 RGB LEDs per module.
https://www.doityourselfchristmas.com/wiki/index.php?title=Different_Styles_of_Pixels
How to ID a pixel chipset:
Look for an integrated IC, black plastic with multiple pins. Read the label, and count the wires. 3 Wires: WS2811. 4 Wires: WS2801, LPD8806, or a few others.
If it is a 5050 LED, count the pins, if it has 4 pins: It could be any number of types, such as: WS2812. Look at the LED diode, if it has a white or yellow stripe across half of it, it could be a RGBW pixel such as the SK6812.
If it is a 5050 pixel with 6 pins, it could be: APA102, APA107. Or a standard RGB LED that is not a pixel.