DRAFT – light up the staircase with an LED strip and tasteless light effects
My initial want was for the stairs to have soft glow lighting … but what the hec, LED strip lights do more than this. Should they animate when approached? Yes, they animate and I can control what they do with an app on a phone or laptop, or set times for effects, or have them react to music, or sync with other house lights. Or if that’s looking too crazy shout, “Alexa, turn off the stair lights”.
And you don’t need anything else but if you use Home Assistant you can control it with that. My cost was £35 but I’ll mention alternatives that cost less in money and effort.
My LED strip runs 2m along one side of the stairs. Power enters from a void below. I can bathe the stairs in stylish light or let rip with insane animation. Instead of a motion sensor I used a tiny but sensitive microphone to react to movement or footsteps. The result is tidy and no staircases will be harmed in this experiment.
a kit alternative to a DIY approach
You could replace my soldering and technical input by buying a ready-made iRGB LED kit. It’ll be less flexible but you’ll find a lighting pattern that gives a pretty good ‘wow’. These kits stretch to 5 or 10 metres – a length which is easier to handle using 12v LED strips and a 12v power supply. They can be bought with a choice of IR remote, phone app Bluetooth control and music sensitivity. If you buy an LED strip that’s a bit long some kits let you cut them to length. Sometimes a kit is set to control a certain number of LEDs. If you cut the LED strip shorter they’ll still work, but some effects will seem ‘off’. Many LED strips have cut-lines marked on them and of course you ought cut from the not-wired end.
how my staircase LED project works
The main feature of my project is a WS2812b light strip with 30 or 60 LEDs per metre and a three-wire connection. As well as a plus wire (usually red) and minus wire (white) there’s a signal wire (green) that tells each individual LED what colour to show at any instant. That helps explain why I’ve used WS2812b ‘individually addressable LED strip’ where any LED will turn on as needed. The lighting effects are managed by WLED software. This software runs on an ESP32 chip which is easier to set up than it sounds.
Take note that this LED strip, and the ESP32 controlling it, runs on 5 volts (any more volts will fry the system) and this low voltage is soon attenuated by long wires. If my staircase was any longer than the 2m of LED strip I needed, I’d need to feed the strip with red and white wires from both ends to reduce voltage drop over distance.
When the ESP32 chip sends a data signal down the green wire it sends a stack of brightness instructions for each LED in the strip. The first chip within the strip obeys the first instruction in the the stack. The stack of instructions now pass to the next chip in line. Ultimately amazing effects appear like magic.
the items you need for a staircase LED project
- ESP32 development board eg a mini-ESP32 MH-ET LIVE
- Dupont male to female wires if you’re OK with soldering
- Dupont female to female wires if you buy components with pre-soldered pins
- INMP441 microphone – if you want the light to respond to a noise
- three core mains flex from the 5v power adaptor to the LED 3-pin JST connector
- optional heat shrink tube in different sizes eg 2mm 3mm 4mm 7mm
- 5v 3amp or more power adaptor with 5.5mm x 2.1mm male barrel connector
- 5.5mm x 2.1mm female barrel connector CCTV style
- 5V dc WS2812B LED strip 30 or 60 leds per metre; white PCB; IP65 protection; 2 metres length. Before you install it look for an arrow printed on the strip: you’ll be sending a signal down the strip in that direction. Tip: if you don’t have a JST plug, cut off the redundant 3-pin female JST connector you’ll find at the far end of the strip.
- optional: aluminum profile U Style for 5050 led strip, milky cover – sold in 0.5 metre lengths with clips included
- microUSB cable to install software plus FTDI driver software
- ESPHome flasher software
- project box or snack box
- optional for additional control, Home Assistant running on a Raspberry Pi – setup tutorial
how many LEDs and how big should the 5v power supply be?
My 2 metre strip has 60 LEDs per metre making 120 LEDs in total. You can use 30 LEDs per metre if the staircase is only viewed at night. An aluminium channel diffuser cover helps to obscure a smaller number of LEDs.
Each LED in the WS2812B LED strip draws around 60mA at full brightness. My strip has 2 times 60 LEDs in the 2 metre strip so to power the strip to full brightness will need 120 times 60mA making 7300mA or 7A. To be safe a 5V 10 amp power supply (~50 Watts) powers this easily. Do use 20AWG (0.8 mm2) wire at least. When the 120 lights aren’t fully on, and they’re animated the power draw will be much less.
the wiring – for lighting effects
The left of my diagram below shows the ESP32 wiring for lighting effects; the right side shows the six additional connectors to include a microphone.
For the left power and LED control side only, start with the 5.5mm female barrel connector which plugs into the 5v power adapter. Use a decent thickness 3-core cable (eg mains lighting flex). Splice into this the male ends of three Dupont cables – fit some heat shrink tubing over any bare connections. Why wire it like this: while the blue board uses around 300mA power, the LED strip might draw 6000mA power.
For the right microphone side, fix six Dupont wires to six pins on the ESP32 board, and six pins on the microphone. You can follow this ‘digital microphone hookup’ guide and change my choices (VCC 3.3v to VDD on microphone; pin 32 for SD; pin 22 for WS; pin 18 for SCK and finally GND and L/R each to GND).
what wire diameter AWG should I use for 5v LED projects?
For the power wires, not the single signal wire, I’d use wire that’s as thick as possible without it being unmanageable. I use 16 AWG (thicker) and use 18 AWG (thinner) when that’s too thick. The examples below might explain why I taught myself to solder my own plugs and wires. In short, the sellers of ready-made cable rarely specify what you’re buying.
My wires are never more than 0.5m (18 inch) in length for 5v LEDs. (I’d use a 12v LED strip if I needed over 2 metres or had more than 120 LEDs – but that’s a different set up to the above).