Is it possible for that 2 arduinos to read the sensor`s value if i connect the circuit as the picture??
If the color sensor is a TCS230 / TCS3200 then it is going to be difficult to do it as you suggest because the reading of the sensor is not a passive activity. The Arduino must first tell the sensor which colour element it wants to read and 2 Arduinos managing the same sensor could lead to conflicts.
You can always work around that with tricks to arbitrate between the 2 Arduinos but probably better is to have one Arduino reading the sensor and the other Arduino obtaining the results indirectly form the first (over say a serial connection). I am also curious to know why you want to do this.
Actually i am doing a colour sorting machine with counter and other features.
but the number of pins is not sufficiant.
For example, I have already set red=1, blue=2 and soon.
Can i set one of my digital pin as output and send to another arduino??
State what sensor you are using and post a link to the data sheet or the product page of the supplier (Ebay etc.). Port expanders could be a solution to insufficient pins.
Welcome to the forum.
Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.
Can you give us a list of your I/O and what pins you are using.
What model Arduino are you using?
What is the colour sensor?
Can you please tell us your electronics, programming, Arduino, hardware experience?