Can anyone give me a link to a electronic device that can measure a distance from 4 meters range...
Or how to make one.

I searched the term "measure up to 4 meters distance" and found this:

https://www.google.com/search?q=meas...ient=firefox-a

And this is one of many:

New Fluke Laser Distance Meters instantly, accurately measure up to 100 meters

Thank you very much... big help.. I hope its available at local stores