After getting a satisfactory result from a prototype, we tried a single multiplexer(MC14067BCP MUX) instead of two arduinos with 16 input pins. Fortunately, Chris already tried a single multiplexer so he let us know how to build a circuit board and a code for it. His guide was really helpful. (Thanks Chris!) We needed 10k resistors between every input pin and every ground which were 16 . It was really cool that we used only an anolog input and 4 address pins on an arduino but a multiplexer could send 16 different values with a binary such as 0000,0001,0010, 0100, 1000, 1100, 0110, 0011, 1001, .... 1111. After building a circuit, we connected all wires from a prototype to a breadboad. We were almost ready to try a multiplexer.