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Multitouch – How To

How To Make a Multitouch Surface

There are several ways to make a multitouch surface. There are capacitive, resistive, acoustic, and other non-traditional techniques. Our focus will be on optical techniques since they are the easiest and most cost effective for the average person to create. The most popular optical techniques are:

  • Frustrated Total Internal Reflection (ie. Perceptive Pixels)
  • Rear Diffused Illumination (ie. Microsoft Surface)
  • Front Diffused Illumination (ie. MTmini, MTbiggie)
  • Diffused Surface Illumination
  • Laser Light Plane
  • LED Light Plane

Optical Multitouch Techniques

Each technique utilizes 3 main components:

  1. Infrared Camera (or other optical sensor)
  2. Infrared light
  3. Visual Feedback (projector or LCD)

setup thumb1 Multitouch How To An infrared camera is pointed at the touch surface and detects when fingers/objects touch the surface. Infrared light is used to distinguish between a visual image on the touch surface and the objects/fingers being tracked. Since most systems have a visual feedback system where an image from a projector or LCD is projected or placed below the touch surface (the MTmini does not), it is important that the camera does not see this image when tracking objects/fingers on the display. In order to separate the objects being tracked from the visual display, a camera can be modified to only see the infrared spectrum of light (by removing the infrared filter and replacing it with a visible light or bandpass filter); this cuts out the visual image from being seen by the camera and allows the camera to only see infrared light that illuminates the objects/fingers on the touch surface. The projector is connected to a computer in order to display the software on the touch surface. The camera is connected to a computer and a tracking application uses the camera image to track and create touch coordinates.

6 Optical Multitouch Techniques

Click the image or title to view a description, diagrams, images, and other resources about a particular technique.

ftir icon2 Multitouch How To Frustrated Total Internal Reflection
rear di icon2 Multitouch How To Rear Diffused Illumination
front di icon thumb11 Multitouch How To Front Diffused Illumination
dsi icon thumb11 Multitouch How To Diffused Surface Illumination
llp icon2 Multitouch How To Laser Light Plane
ledlp icon2 Multitouch How To LED Light Plane

Software

Resources

This page is still being developed. Stop by often to see updates and more information for building your own multitouch surface.

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  • toey

    Innovative

    • http://sethsandler.com/blog Seth Sandler

      Thanks!

  • ToMayz

    Hey, is there something like “Right Mouse Button”?
    If not I prefer to make it a little square space in corner of touchpad, what do You think about it?
    Greets, ToMayz.

    • http://sethsandler.com/blog Seth Sandler

      I’m not sure what you mean. Can you be more specific?

  • zach

    how to set it up and are there any games you can play with it

  • Josh

    i never see something like this before

    im so happy about technology

    :D

  • http://www.cyworld.co.kr/01099457582 Sunghyun

    hey im your follower !
    i got real interest about your youtube video !

    im university student in korea
    we have project just like your product on youtube
    would you please teach me how to make this product?
    you can touch me with e-mail

    andrewsbang@hotmail.com

    thx !

    • http://www.sethsandler.com SethSandler

      Hi Sunghyun,

      I’d recommend going to nuigroup.com and downloading the multitouch book. That’ll get you a great head start. :)

  • http://www.thenorthface-outlet.org/ the north face outlet

    how to set it up and are there any games you can play with it

  • http://profiles.google.com/mad.predator MAD RATT

    Hello. Can you please tell me what kind of infrared camera did you use in the youtube clip? thank you:)

  • Marc

    Hello, im currently working on a project using a multitouch display.
    Im researching new materials and physical feedback of touchscreens.
    Do you heard about multi-touch screens that work without beamer and Cameras behind the screen? i think of something like the Iiyama ProLite T2250MTS-B1, with two cameras in the edges of a LCD Screen.

    ps: really nice blog ;)

  • Rub-a-dub

    how small can this be made.

    • http://sethsandler.com/blog Seth Sandler

      As small as you’d like really. The camera needs room to see the surface though, so a little depth is necessary.

    • Rub-a-dub

      tring to make a wacom cintiq clone can. Is is possable with this?

    • http://sethsandler.com/blog Seth Sandler

      You can try, but it won’t be anywhere near as good. It won’t be pressure sensitive and the resolution won’t be that great for drawing anything complex. It’d be better to buy a wacom tablet and project onto it.

    • Rub-a-dub

      tyvm for the help. Is there another avenue that you know of that I might try looking at?

  • http://pulse.yahoo.com/_PZAPLL3HN4CXDYAVX7FL5V6DFQ Ric

     Hi, noticed that all the examples I saw used a projector as the visual feedback device. Can an LCD be used instead? Do you have any examples of how to make this happen? Thanks.

    • http://sethsandler.com/blog Seth Sandler

       On some of the techniques you can use an LCD. You can learn more about that on http://nuigroup.com/forum.

  • Sid

    hey in the video you didnt mention infra red lighting why? can you tell me because i dying to try this and i have all the parts and just saw the diagram showing infrared lighting!

    • http://sethsandler.com/blog Seth Sandler

      Which video do you mean? If you mean the MTBiggie video, it is mentioned. You only need infrared lighting if using a projection.

    • Sid

      so i need to buy infrared led’s i thought led’s wont be needed in Front Diffused Illumination technique but thanks!  ! thanks!! can u send the circuit of the led’s nd sorry for my bad english english isn’t my first language!
       

    • http://sethsandler.com/blog Seth Sandler

      You need an infrared light source. You can buy IR illuminators for front Diffused Illumination. If you need more help or have more questions, I suggest visiting http://nuigroup.com/forums for a lot more information and people to help you.

  • Anasmoin

    any thing other than a projector can be used???

    • http://sethsandler.com/blog Seth Sandler

      You can use an LCD screen, but it’s more work. You can learn about that in the Multitouch Book linked above.

  • Pingback: Make a Multitouch Surface - electronics projects | Make, Electronics projects, electronic Circuits, DIY projects, Microcontroller Projects - makeelectronic.com

  • Pingback: Make a Multitouch Surface - electronics projects | Make, Electronics projects, electronic Circuits, DIY projects, Microcontroller Projects - makeelectronic.com

  • http://www.facebook.com/people/Eli-Luna/100000248011130 Eli Luna

    Hello, you can combine a field of infrared light (laser) LED light?
    I mean maybe if you combine a better quality to the touch with the infrared camera
    I guess it can work because it creates a plane of light led, but leave as a means of infrared
    can? Thank you facin me your work

    • http://sethsandler.com/blog Seth Sandler

      Yes, you can combine techniques if you’d like. It’ll work.

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