Hi everyone.
I'v just moved house and now have a decent sized staircase to get from the drive to the house.
At night its almost pitch blank and you need to use a torch to see the stairs.

I have ordered some led strips which I am going to put under the hand rail to give light, but in a nice way, rather than just having a light on the roof shining down on you.
I want to make it a little fancy though, rather than just having the lights on all night.
My plan was to put a sensor at the top and bottom and a micro controller to fade in the lights when the sensor is tripped.
The problem im having is a PIR sensor triggers too much due to cars driving past, and the bushes moving in the wind. and I cant get a good trigger point which activates only on a person walking up the stairs.
So my plan was to move to a laser style tripwire. the ones they have in shops to ring the bell when you walk though.

The problem I have is I cant find a cheap "Kit set" one anywhere.
All the ones i can find online are expensive all in one sets. mostly wireless, and with the doorbell unit.
Where as I just want the sensor I can wire directly into my arduino.

I was thinking of making my own with a $2 laser pointer and light sensor, but I have no idea how feasible that is.
During the night it would work, but I also want it to work during the day as I want to hook it up to other things such as a doorbell and security camera.

Any ideas where I can get / make a sensor / trip wire?

(Im wanting about 3 as well to put at various points on the stairs to trigger)