Motion sensing, ambient downlit stairs

Hi - I'm trying to accomplish a project similar to this: https://www.youtube.com/watch?v=dECisi8KpDA

The only difference being that I want to have an approximate idea of where on the stairs the individual is.. so in the demo video, if the guy had turned around halfway and started walking back down the stairs, the light trail would follow him.

This means I need to have some approximate knowledge of where someone is on the stairs.

I think there might be a couple ways to skin this cat.. but I'm not sure which route to go. I think the following are all options, but I'm not sure if any one way is better than the others. That's what I need guidance on atm:

  • Leverage an ultrasonic range finder at the top of the stairs
  • Leverage a 25mm PIR sensors per several steps (3-4) to approximate the movement of the individual
  • Leverage 10mm PIR sensors on every step to have a more exact estimate of the location of the individual
  • Leverage an IR emitter/receiver proximity set-up similar to this: http://www.instructables.com/id/Simple-IR-proximity-sensor-with-Arduino/
  • Utilize a presure sensor under each stair
  • Use a highly sensitive vibration sensor on each stair

To give you a rough idea what the stair passage looks like and some of the ideas I'm toying with, here's a really crappy CAD rendering... The only thing for sure is the location of the NeoPixel strips and the Arduino.. The location sensors are the wildcard here and I have no idea what the best way to proceed is:

Thanks in advance for any advice!

another option is IR on each step with a receiver on each step. then you know if the individual has changed direction.

dave-in-nj: another option is IR on each step with a receiver on each step. then you know if the individual has changed direction.

Like having the IR on one side of the step and the receiver on the other? I was hoping to mitigate as much wiring as possible.. but I also want to do this right.

you are correct that using a IR and receiver on each step would double the wiring....

er.. you are using neopixel strips....

increase the wiring 10 fold !

the range finder would work as long as no two people were on the stairs the IR does not discern 1 person from 2 people.

the range finder seems to solve more issues.

Yea, but with the NeoPixels, they can be run serially off a single digital pin.. so that helps.

The other concern I have with the ultrasonic sensor, is I don't know the radial area that it can sense. All of the ultrasonic sensors on Amazon and other stores give you a good idea on the range.. My concern is that the ultrasonic sensor might only pick up people that are a certain heaight, or that are walking in the exact middle of the stairs.

how about this

https://www.sparkfun.com/news/1404

https://www.youtube.com/watch?v=4yFqBO0nKMA

Greensprings:
how about this

Check out the LIDAR-Lite Distance Sensor - News - SparkFun Electronics

Rotational range scanner with Arduino and MATLAB - YouTube

I’ll keep an eye on it… but it isn’t available for purchase. (thx, btw)