Light Emitting Diode Pixel
Frequently Asked Questions:
What`s an LED Pixel?
LED Pixels are individually controllable Red , Green and Blue LEDs in one tiny package, the LED itself has a tiny LED driver built in, the pixel just needs power , ground and data in and out.
How many wires between Pixels?
Only ONE between controller and the first pixel and in between each subsequent pixel.
Power (+) and Ground (-) are wired in parallel to all the pixels. and Data In and Out pass through the pixels. (As noted below some types of pixel may have a Backup Data or a Clock Line)
Each pixel takes its part from the Data Incoming stream on the Data line and passes Data Out to the next pixel in the chain.
Total of THREE wires for thousands of individually addressable LEDs
No need to wire each LED individually back to the controller.
What voltage do Pixels work on?
All pixels use 5V on the Data line.
Pixel strips supply voltage is usually 5V or 12V with individual control and 24V with groups of LEDs forming pixels.
Pixel controllers will often function from a supply of 5V to 24V they all output 5V on the Data output.
How far can I go from Controller to first Pixel and Pixel to Pixel?
Datasheets for most pixels recommend a maximum distance of 10 meters (33 feet ) between control and first pixel and pixel to pixel.
We recommend trying to keep distances to a maximum of around 5m or 16 feet between pixels in general.
APA102 and similar separately Clocked Pixels are very sensitive to distance and useable speed will drop considerably over long distances.
How many Pixels can I have in a single run?
Some controllers can control 2000 pixels from a single output, because the data has to pass from one pixel to the next, Pixel 2000 will get its instructions with a delay after Pixel 1. This is not noticeable with slow abstract patterns.
With patterns that need to synchronise, 800 pixels per output in a single run is a general rule of thumb.
I need to go more than 10 meters (33 feet) from Control to Pixel and Pixel to Pixel , how do I do that?
Null Pixels , amplify the signal and can allow for extended distances between Control and Pixels or Pixel to Pixel.
If there are issues with electrical noise corrupting the data , Null Pixels will also amplify the noise. They are not a solution in every case.
Long Distance Pixel control uses a twisted pair differential signal , the compact transmitter and receiver pairs connected by common and cheap Cat5/6 network cable to transmit Pixel data easily to 100m+ (330+ feet) without noise corruption.
What is Power Injection?
On long runs of LEDs, the Voltage can drop because of the resistance of the wiring or LED strip.
RGB strip will show this as Yellow fading to Amber and then Red as the Green LED fades needing a higher forward voltage.
To solve this, a pair , + and -, of extra wires is run directly from the same fuse for the run to a `injection` point along the run, this extra copper from the wiring beats any voltage drop along the strip.
Typically, add power injection on 60 LED per Metre strip at every 5M , conveniently where the strips have a connection already.
Can I have Pixels in my car / van / boat / motorhome / truck?
Yes , of course you can. Low voltage LEDs can be powered from any battery source.
Why do some Pixels have 2 data connections?
Not to be confused with pixels that have a separate Data and Clock line like the APA102.
Pixel types such as WS2813 and WS2815 have a DI , Data In with DO Data Out and BI Backup In and Backup Out.
If an individual pixel fails , the Data will transfer to the Backup data line and the failed pixel will be bypassed rather than everything downstream failing.
The BI data line is Not Connected at the controller, and can be left floating,,unconnected, or tied to ground, it is recommended to connect both DI and BI at any connections further down to continue integrity.
Why do some Pixels have a Clock Line?
APA 102 and WS2801 are examples of pixels with separate Data and Clock lines from the controller, this should allow a much faster refresh rate , less visible flicker with fast moving images, issues with high clock rates over any distance, over couple of meters, makes these pixels more suitable for Persistence of Vision, P.O.V. displays and juggling props than long range applications.
What does RGBW mean?
RGB can mix any colour of the rainbow, most pixels are RGB.
Red ,Green and Blue on together will mix to White light, as can see requires all 3 LEDs on and the White can appear a bit cold. Adding a White dedicated LED to the pixel , allows pure white at less power and some more subtle pastel colors to be achievable.
Why all the different type numbers?
World Semiconductor are probably the most common manufacturer and their parts start with a WS , like WS2811, OPSCO parts have a SK part code and Genesis Systek start with a GS.
All of these can be controlled using WS2811 compatible controls.
These are all just different manufacturers and LedShed selects the most appropriate products for the application.
We are always here to help, please feel free to Contact Us