So we did the serial port miroring activity. We were a lot because we needed 3 teams : A, B and C. Each had a computer and an arduino card.

Firstly each team had to put the right wires and the right files (thanks to a software)on the arduino card.

The job of team A and B is the same. Both have a side of a big grey wire full of smaller wiles (blue orange and green). The goal ? Simply talk to each others ! Send message through the wires with a monitor window. In fact it didn't work at the first try. The difficulty is that Team A had to put the blue, orange and green wiles in this order, and the team B the blue, green then the orange. Like this, the team A sent a message through  the orange wire and team B received it this way. They answered through the green wire. Because you hear with your ears but you talk with your mouth :) (of course it was written in the program)

For team C, it was harder. They had to put crocodile clips on the small orange, blue and green wires after have denuded the big grey wire. The clips are linked to an arduino card linked to a program in the computer. Like this they could read our messages from team A to B. And could hack the communication between us.

So we (team A and B) tried another program. Iwe still had to send messages through the wires, but it was ciphering them (=.encoding). It was  quite simple, the program was delaying the letters.

Each letter has got an acsii code. It means when you type the letter « A », the computer understand the number « 41 » which is A’s acsii code. So to cipher the messages, if you choose a 5 letters delay, the arduino program asks the computer to do « +5 on the acsii code ». Like this, 41 (=A) becomes 46 (=E). So A becomes E if you choose a 5 letters delay, B becomes F, C becomes G ect...

Like this team C only saw crypted messages ! And the team B's program was deleting the delay so the team could see the real messages. (team A and B's program are still the same, they can sent and receive messages encrypted)

If you want to see our power point with more photos, watch the files :)

Quentin, Gabriel, Lois, Mathieu, Paco, Tommy, Baptiste, Hélène