Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Circuits motion detector light assembly 3 way proximity

  1. Oct 8, 2016 #1


    User Avatar

    Is it possible to create a series of circuits capable of detecting a moving object with 3 levels of proximity e.g. green light when object is 10ft. away, yellow light at 5ft., red light at approx. 1ft. away, etc?

    Thanks, Dave
  2. jcsd
  3. Oct 8, 2016 #2


    Staff: Mentor

    Yes. The simplest way I can think of is the photo detector method. Simply shoot a beam of light across the path, and sense when the light is interrupted by a passing object. You can have multiple beams at different distances.

    Automatic doors at stores and office buildings and garage door openers use such photo detector circuits.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted