How do I make this led light sensor

Hello,

I am trying to make this simple laser tachometer: How to build a simple laser tachometer - YouTube

The guy is using a voltage meter and I am trying to make my own with this guide:
http://startingelectronics.org/articles/arduino/measuring-voltage-with-arduino/

But I am not getting results. I am using a arduino yun if that matters.

EDIT: I fixed it. Since I wanted measure the voltage of the LED I could leave out all the resistors. And that's it.

Hiya blastoi, Welcome to the Arduino forum.

I looked at the page you (almost) linked, and have 2 suggestions:

  1. use a simpler board for experimenting. Unless you are 'wedded' to Linux and the Yun, why not use a UNO or other single processor board? This will greatly reduce the complications and just be all around easier to 'get'.

  2. show us what you have put together. This would include your sketch(es), schematics and pictures of the setup. Remember that we don't have the close-up view of your project that you do!

Thanks for the reply, but I already fixed it. I edited the post with the solution.