set-up idea for stairs lighting

Hello all,

I am thinking of making led lighting for under the steps of my stairs.
Because i am quite new to electronics i would like to get some ideas on how to set up this project.

I have already figured out:

  • for fading in/out of led string i need PWM ports.
  • led string used about 4,8 W/m. with stairs of 0.7m this uses 0,28A with 12V
  • to turn on led strings i need mosfet transitors as a switch for the external power supply for each string.

now my issues:

  • i know arduino mega has 14 PWM outputs of witch 2 are for cummunication. (don't think i can use those ports)
  • do i need resistors for limiting current, or is this built-in in a standard led string?

I was thinking at first i could use 2 PIR sensors for detecting someone walking on the stairs, but i understood this sensor uses a digital input. (so 10 left when not using ports 0&1).

then i thought of using multiple arduino's. i was thinking if it is possible to have 2 sensors on regular inputs, then using a number of PWM outputs, and then use a digital output to send to another arduino, so this one could run the other PWM outputs.
But is it this simple?
For example stairs 1-6 fade in, signal to arduino high, then stairs 7-14 fade in.

Anhyhow, i was wondering if some of you had any experince with this kind of projects.
And i'm not entirely new to programming but don't know much about equipent.

If anyone can give me tips, they are very welcome.

thanks in advance.

kind regards,

Geert van der Heide

. for follow
Playing with the same idea, but also pretty new to Arduino.
My idea was to have a LED strip of around 10 LEDs per strip, one under each step. I just don't know how to program that one 10-Piece is seen as a unit so you can program each unit separately.

I made an Arduino Ambilight for my TV, so I know you can talk to each LED separately even they are all connected to the same PIN. I just don't know how since I mainly followed tutorial.

For example stairs 1-6 fade in, signal to arduino high, then stairs 7-14 fade in.

If you want the strips from 1 to 6 and 7 to 14 to light up together, you just need TWO Pwm outputs