So, I wanted an animated flight of stairs. I have seen a few videos on Youtube, where people have either had a strip of white LEDs mounted under the stairs, or LEDs lighting the step of the stairs from left and right. But, I wanted to have the full monty:

• using NeoPixels, as you can control the colour and brightness of each individual LED
• using RGBWW type, as the WW (stands for "Warm White") in there makes it nicer (more natural) light
• base it on the ESP8266; I did not really have any experience with at the start of the project, but I have been told it is awesome
• have it fully automated (IR sensor triggered), that is obvious
• have a separate button or Alexa connected, so that I can show off

My stairs go from ground floor to first floor (I have more, but I wanted to do it on those two flights only). Each flight of stairs has 8 steps - a total of 16 steps. They are about 1m wide.

There are quite a few NeoPixel types around and it can be confusing at first. Most common (for makers) are the WS2812. There is also a type/variant called SK6812, which are fully compatible. Apparently, they have less voltage drop (compared to WS2812) and are more robust - but do not quote me on that, I did not do proper research on those facts. So, I went for those SK6812 ones and they worked fine for me in the end. They come in three styles:

• IP30: these are the normale, bare ones, they have no coating, are not water proof or even resistant, but good for indoor or if hidden from sight (not pictured here)

• IP65: they have a kind of "silicon cover" to protect them from humidity. I have seen people arguing that that will hinder heat dissipation. But, event if that was true, for this project, they are not switched on that long a time and rarely at full brightness. They have a self adhesive tape at the back.

SK6812, 60 LEDs / m, IP65

• IP67: they come in a silicon sleeve, good for outdoors I guess. You can get them in a maximum length of 1m and even then, they are soldered together in about the middle of the strip. According to the Adafruit NeoPixel Uberguide, all LED strips are manufactured in 1m length and then soldered together. They do not have a self adhesive tape at the back, so you might need to buy your own, if you want to stick them somewhere.

SK6812, 144 LEDs / m, IP67

Most of the projects you see out there just stick the bare LED stripes somewhere and that is it. The truth is: it looks shite! Nobody (apart from us nerds) wants to look at PCBs with SMD parts on them. So, here is a crucial tip for acceptance of your (any) project: spend at least 50% of your time on making it look nice! ;)

As I wanted to have it look nice, and I also need to wipe my stairs every now and then, I decided to use aluminium profiles with milky covers. As the stripes need to go under the steps, I picked corner profiles. So I ordered 20 corner profiles, each 1m length. For those, I paid about 80€ plus import tax - but they are totally worth it! They come with a very nice, milky cover, with end caps (one with, one without holes for cabling) and small metal clips to mount them.

Aluminium corner profiles for LED stripes

I wanted to use LEDs in RGBWW (Red - Green - Blue - Warm White) and IP65, with a white PCB. For some reason, that white PCB is a problem, I could not get them from German online sellers, so I had to go with China. What I paid back then is listed below, in brackets are the costs as of writing this Wiki (March 2018):

• 30 LEDs/m -> 37€ (22€) / 5m
• 60 LEDs/m -> 50€ (28€) / 5m
• 144 LEDs/m -> 28€ (18€) / 1m

The other important factor you have to take into account is amperage. The more LEDs/m the more current, the calculations for the LEDs in question are:

• 30 LEDs/m -> 1.8A/m
• 60 LEDs/m -> 3.6A/m
• 144 LEDs/m -> 8.6A/m

With 18 steps à 1m, this amounts overall to:

• 30 LEDs/m -> 1.8A/m -> 28.8A
• 60 LEDs/m -> 3.6A/m -> 57.6A
• 144 LEDs/m -> 8.6A/m -> 138.24A

All at full brightness of course. Now, the last one is out of the question, I am not having a cable running 138Amps in my house, now way! Also cost would exclude those for me. The 57Amps, would possible be fine. But in the end I decided - per pure gut feeling - for the 28.8Amps, i.e. the 30 LEDs/m type of stripes. One: it was cheaper, two: it was likely be bright enough and three: the current consumption.

BTW: I ordered all of this from China.

For the main (5V) power cables, I used 2.5mm^2 (proper) copper wires, which I did not order from China, but from Germany. I wanted to make sure, I am getting good material. 2.5mm^2 can carry about 32Amps (per German norms), so I have small, but some safety. As they are not lit for very long times and rarely at full brightness, this should be plenty. They run like a "bus" along the sides of the stairs. At every step I removed the isolation at about 5mm and soldered wires (0.2^2mm) to them, carefully restoring the isolation with electricians tape. They then end in a Dean plug. For the signal in and out I used 0.14^2mm wires, which end at every step in a JST plug. I then manufactured the light bars from the profiles, with corresponding plugs and I can now easily replace them, should they break. I was a bit concerned, as my landing (between the two flights of stairs) requires about 3.5meters of cabling from the last LED of the first flight to the first LED of the second flight of stairs. But I am experiencing absolutely no issues whatsoever.

Power supplies is the next thing: I have a standard one from eBay, which supplies about 30Amps. Close, but it works and does not really get even warm.

For me the choice was clear, it is going to be an ESP8266. I only played around with it for a few hours, when I started this project, but it seemed to be able to do the job.