Hi there, I am a mechatronics student from Serbia,and at the moment I am designing a modular main board for autonomic robots.
I am having some trouble with the analog inputs module. The basic idea of the whole main board is to be as simple as possible, since it is intended for educational and practical purposes for younger students. The practical part is intended for making a robot which we do on one of our courses,and since it is meant to be easy for use I have designed the analog input part so it has the possibility to use both analog sensors which give a current as a output or a voltage. So for the sensors that give current I have made a current to voltage converter with a opamp,and for the sensors that give voltage I am using a different opamp that has a gain from 1 to 11. You select which opamp you want to use with a jumper. So the problem is with the outputs of the opamps. They both go to the same input pin of the MCU,and I don't know how to connect them so they are not shortened one to the other.
Some solutions that I am thinking about are:
-Use a jumper at the output also ( but I am looking for a more elegant solution)
-I was thinking of some solutions with diodes,but I think they will cause problems with the signals since they are non linear components.
-Multiplexers are not an option since all of the pins of the MCU are used for other stuff so there isn't a way to generate the selection signals.
On the pictures left side is the basic idea,and on the right side is the solution with diodes that I am uncertain about.
Please bear in mind this is my first project,so there can be,and probably are some rookie mistakes.
Also any kind of ideas and tips are welcome.