At the moment I´m studying mechanical engineering at the university of applied sciences Würzburg Schweinfurt. I´m working at a project which should identify errors of a TPU foil. To realise this application i´m trying to use light behind the foil and detect the light which gets through it.
First i´m going to try if the LDR works. Next step is to try it with more than one LDR. The arduino uno only has 4 analog inputs. How can I extend the inputs pins? Did anybody use a multiplexer before? Would this be a solution? The LDR has a width of about 4 mm. I will need at least 256 of them.
The Uno has 6 analog inputs, some Arduinos have more.
You can use a multiplexer to increase the number of analog inputs. You may have to allow time for switching or take an extra reading when switching'
You might also consider other approaches such as a video camera with a digital interface to the Arduino.
i´ll try it.