Magic LEDs

There is a company called Xinglight that make some LEDs that I use. I call them magic LEDs because they are really so useful.

They cost 2p or less each, but they are RGB, so full colour LEDs. Now bear in mind some other single colour LEDs I use on some boards are more like 5p each, these are cheap.

So what makes them magic apart from they price?

• They work from 3.3V (datasheet says 3.5V min, but my tests, room temp, 3.3V just works)
• No need for extra series resistor as normally needed on an LED - no need for any extra component.
• Uses WS2812 serial coding so one can have one or more of these on a single GPIO pin.
• Full colour
• Tiny

So if I want a simple status LED on a board, this is a tiny, 1x1mm component on a single GPIO on the 3.3V supply, and just works. Yes, it is more complex than a simple on/off GPIO, but in some ways that is better is it cannot be on accidentally - it needs the correct code to send the correct sequence to light it up. If this status LED lights up the code is running, meaning it all works, boot loader, signature check on code, code running.

The small ones are 1x1mm, and are really so small. I have used for years on many designs, but it is time for a change.

Why?

These tiny 1x1mm LEDs can snag and come off the PCB very easily.

So what is the alternative? Well, they do a 1.6mm x 1.5mm version and a 2x2mm version.

My current plan is changing all my designs to the SMD1615 (1.6mm x 1.5mm) version.

It has castellated pads, so some chance of solder coming up the sides, and is not that much bigger really.

I usually pack the 1x1mm LEDs at 45 degrees, space at 2x2mm, and can do that both ways, just. The new LEDs can do 2mm spacing straight and neatly. They can fit closer, just, but not both ways if I want to make a grid.

So for single status LED - no brainer, takes about the same space, and easier as a track can run under it.

For a row of LEDs at 2mm spacing, perfect.

Indeed, almost all of my designs work, even the coaster which is 124 LEDs in rings!