7

LED screen

GB LEDs are a wonderful invention

that allow us vast amounts of visual

creativity in our builds. You can

light things up as subtly or as garishly

as you like. In reality, these lights

aren’t a single thing, but three tiny

LEDs mashed together in one package. This means

that to control them you need three pins – one for

each colour. This quickly adds up and, even with

multiplexing, it’s hard to control much more than a

grid of ten by ten RGB LEDs. Fortunately, help is

at hand in the form of the WS2812B, which is an

RGB LED with embedded microcontroller. These

have a really simple networking protocol, so that

each has an input pin and an output pin. Attach a

microcontroller to the input pin of one WS2812B,

then attach its output pin to the input pin of the

next, and you can daisy-chain a string of these LEDs

almost as long as you like, (the only limits being

power and microcontroller memory).

These little LEDs are best known as Adafruit’s

NeoPixels, but the same part is available in a lot of

forms from a lot of sellers – and crucially, they all

use the same protocol, so you can use the Arduino

NeoPixel library to drive them.

We ordered an 8 × 32 pixel flexible display for

£25.61 from AliExpress store Ledworld. That’s 256

LEDs. The first thing you need to realise when using

this number of LEDs is that you’re not going to be

able to use a simple power supply. At full brightness,

DIRECT FROM

SHENZHEN

R

Lighting up the world 256 pixels at a time

By Ben Everard @ben_everard

Below

Even at low

brightness, the

colours stand out

and are easily visible

REGULAR

Direct From Shenzhen