LED Strips

There a lot of options for colour LED strips.

I am talking pretty much entirely about 5x5mm individually addressable full colour LED modules on a 10mm wide flexible PCB with leads at each end. But even being that specific there are a lot of choices!

These things basically...

Covering/backing

Start with something simple - these strips often have options.

• Black or white strip supporting the LEDs.
• A domed flexible clear covering that is generally pretty waterproof.
• A rectangular sleeve enclosing the string, which is more waterproof.

This is really a simple choice. I have some on a door frame which are the domed covering, because the strip or chips would snag otherwise. I have some on a shelf (image above) with no covering, as out off reach. You need to consider this if putting in some sort of diffuser, e.g. an aluminium strip with plastic cover - where no covering in the strip itself helps much under the diffuser. A diffuser is usually a good idea.

Now, some do come in a diffuse housing, which can be a good compromise. Bear in mind that any covering or enclosure makes cutting to length and joining harder. The simplest is the bare strip with LEDs on it (and the pads between them) allowing easily soldered joints to another strip. There are clips you can get but I do not recommend them - soldier it.

Note - the adhesive backing is pretty universally crap, not bad on aluminium, but on wood, etc, not good. I'd think about some nice 3M tape.

Density

Again a pretty simple one - how close the LEDs are - and that varies.

1. Close together is great for sheer amount of light, and using inside any sort of diffuser strip as you can hide that there are individual LEDs.
2. Close together means more LEDs and so more power needed.
3. Close together adds to the cost.

Voltage

This is a bit more complex. The main choices are 5V, 12V or 24V. I am generally working towards 12V these days (with per pixel control on a WS2815).

1. 5V can mean notable voltage drop on long runs, meaning power feed in at extra points. 12V can run longer and typically the modules can work on much less than the full 12V if they are per pixel 12V.
2. 12V and 24V can be multiple pixels on one controller, e.g. 3 RGB pixels on one controller in a row are controlled together as the 12V is split over them. This is pretty shit, to be honest. It is not always the case, and WS2815 seem to be ideal with single 12V working pixels separately addressable.
3. Higher voltage is lower current and can be a smaller power supply and less heavy duty power leads.

Current

This is one of the big issues, and not as simple as it looks - the LEDs do not use a lot of power, but there are a lot of them. Higher voltage means you can work with lower current. But you have to be careful, even with 5V DC levels, if you have hundreds of amps available - that can be nasty stuff (not that is unlikely to electrocute you, but can burn and melt stuff - a short at that power can melt copper wires).

The other issue, apart from not wanting to handle large currents (for which higher voltages help) is the power supply itself. A high current power supply is bulky and expensive.

A big challenge is working it out - and this can easily go wrong. There are guides and tools and data sheets. But you can easily find you are massively over specifying your requirements. As with any modern electronics, LEDs are getting more efficient and so lower power - the guides for 10 years ago do not apply now.

You also have the option of not lighting all LEDs full white all the time. So depends what you want. In practice you probably do want almost any system to work at all LEDs on full - but not always!

In short, my recommendation is to test the strips you are using, get a current meter, a strip and set to full power all on. Measure it. Note if can change on temperature, so leave a little overhead. But that tells you what you need.

Bear in mind voltage drop is also a thing - all white on a long strip could have more than enough current from the supply but still fade and lose colours at the end due to voltage drop - sometimes you need extra power feed in along the strip(s) to fix that. This is were 12V can help if the pixels can work down to half that (as seems the case) you can tolerate a lot of voltage drop.

I have a fence where along side the chain of strips I have a thick copper power pair, which taps in at each strip join. That works a treat as the thick copper power cable is low resistance and allows the current to get to the whole strip. The same power supply, which clearly has enough power, could not work the whole chain from just one end as the voltage drop would kill it after about the second strip. Bear in mind, whilst the data has to connect at one end, the power could always connect in the middle of your set up.

Never forget - power ends up as heat and has to go somewhere.

Colour options

There are two main colour options.

• RGB - the simplest type - full colour using Red, Green, and Blue
• RGBW - an extra 4th White LED.

There are some RGBWW with two different shades of white as well, but rare.

the main advantage of RGBW is that the extra white LED is usually very bright (and often available in a specific shades of white), but is also one LED, using less power than combining RGB to make white. Yes you can go overkill and try RGB and W for even more bright and even more power usage.

The general idea is if the strip it to be functional lighting as well as pretty effects, RGBW helps allowing the white to be lighting. You also often want to consider higher density of LEDs in such cases.

Chip type

There are a few chip types, and many odd chips that are compatible. There seem to be some subtle differences in the data sheets but in practice they all work the same way.

• WS2812 is the main one, simple RGB 5V
• SK6812 is another one, typically the order of colours is different in the data sent
• WS2815 is the one that does RGB but using 12V
• There are new WS2815 that are 12V and RGBW

Timing

Rarely an issue, but worth considering - each pixel on a strip takes time. So the maximum update rate of a whole strip depends how many pixels. Each bit is approx 1us long, so each colour is 8, and each RGB is 24us. That means 100 RGB takes 2400us or 2.4ms. RGBW is 4 colours, so takes longer. As you can see, once you have hundreds of pixels the refresh rate can come down and start to be more noticeable. The answer is more separate strips working in parallel if your controller can do that. I'm practice, it is rare for many hundreds of pixels and rare that the refresh rate matters that much. But bear in mind on large installations. 

Duff pixels

One of the reasons to look at the chip type is the WS2815 has a backup data line. The way this works is the data daisy chains from one module to another - any break, or any failed module means the whole of the rest of the strip dies. The WS2815 has a cunning plan - a backup data that goes directly on to the next pixel. The idea is that if a module fails, the next LED picks up the backup line, and delays one pixel, meaning it works and so does the rest of the strip. Only if two adjacent modules fail does the rest of the strip die. This is an excellent innovation, and I definitely recommend it.

Recommendation

The recommendation is simple...

• For density - decide what you need.
• For covering and strip PCB colour - decide what you need.
• Recommend WS2815 RGBW 12V strips - only now available in 2025.

The reasons are simple.

• 12V working is less current, so smaller power supply.
• 12V allows more voltage drop, so longer strips just work.
• WS2815 backup data allows a duff pixel.
• RGBW allows more powerful white at lower power.

(I have some of these latest strips on order).