So basically, you step in front of the house door (straight line of sight for about 3 meters), a motion detector detects you and all the LEDs turn on to white. Then as you step forward, 10-15 LEDs in front of your steps change colour to "guide" you through the walkway.
My problem is, I don't know what's the best way to follow the steps of the person. Currently I have thought about the followings:
1- Having PIR sensors through the walkway, maybe 10-15cm apart, when one detects something in front of it, then the LEDs passed the sensor turn on. The issue is, what if you miss one of the sensors by not stepping in front of it?
2- Ultrasound distance measurement to get the distance of the person to the door and changing the LEDs.
I appreciate if anyone has any more ideas on how to track the movement of the person down the walkway?
Most commercial PIR sensors are constructed (via optics and electronics) to only sense motion across the field of view.
Standing still in front will not register as a continuous detection, only the entry and exit from the field of view will be detected.
Ultra sound is problematic as "soft" targets like clothing have a weaker return (echo) and that reduces the detection range. How about a series of IR "trip wire" sensors. Modulated IR LEDs on one side of the path and IR detector/decoders on the other. There are detectors made to work with constant input and detect and report interruption of the "beam",
Optical beam sensors or pressure/weight sensors would probably be the most reliable. A pressure/mat sensor might be the easiest but may not integrate with the Architecture/landscaping.
...You could "fake it" with one sensor at the beginning, sequencing-on the lights slightly-faster than you expect someone to walk.
I've noticed that grocery stores are starting to use PIR sensors to turn-on the LED lights in the freezers as you walk down the freezer section isle. But, the distances are probably longer than your steps/walkway so they don't have to be super precise.