20,115 views 10 comments

Laser Light Plane Multitouch Technique

In LLP, infrared light from single or multiple lasers shine just above the surface. The laser plane of light is about 1mm thick and positioned as close to the touch surface as possible. When a finger or object hits the light plane, the object lights up and  is seen by an infrared camera below the surface. An image is displayed by using a projector connected to a computer pointed towards the projection material.


Parts List

  • Clear, Flat Surface (Glass, Acrylic, Polycarbonate, Plexiglass, etc.)
  • Infrared Laser(s) – Lasers can be placed in each corner of the surface
  • Line Generating Lens – Creates a thin light plane
  • Projection Material (Rosco Grey, Vellum, Mylar, Paper, other, etc.) – For displaying an image
  • Infrared Camera/Modified Webcam

Video Examples




Did you enjoy this post?

Comment Below , Follow Me on Twitter , Follow Me on Facebook , or Network with Me on Linkedin

  • Can you provide any details of suppliers to provide the lenses needed for this technique, and also the laser led suppliers.
    Question, would a frosted panel work as the projection surface instead of trying to put a projection surface over the perspex sheet?

  • Aalay

    how does it detect multitouch ? what is the use of multi touch?Is it runs on different applications?

  • Hassan elbaseri

    Hi , its so nice work . I have question, do you use image processing algorithm and which algorithm used, i would like to inform me about other application.

  • aman motiyar

    hey seth,
    i have mailed you my problems regarding LLP screen.
    but there is no response from your side.
    please send me the solutions as soon as possible.
    thank younn1

  • aman motiyar

    I sent you my problems on your blog. Anyway brother
    Problems are:
    I have a acrylic sheet(2.5ft * 2ft * 8mm) and have four grooves on the corner of the sheet..
    I bought ir lasers from peau production and line lens of 120. Degree
    And a modified sony ps3 camera
    Now at which angle i should place the lasers so i can get perfect blobs..
    Means tappered aur straight..
    And what should be the height between sheet and camera.

    • The camera should be placed far enough to see the whole piece of acrylic. The lasers should be placed perpendicular to the acrylic so the there’s a plane just above the acrylic. I’d also recommend talking to Nolan from Peauproductions.

  • Jean

    What must be the power of laser modules? Does 1mW is enough ?