Tic Tac Toe via 9 RFID Readers

Hi,

I'm currently working on a school project. My goal is to develop a Tic Tac Toe like game using nine RFID Readers and an Arduino YUN. The idea is to hold a tag on the RFID sensor and a X or an O will appear on the monitor at the right place.

I have pretty much finished this project, but I still have one big problem. All the readers hardly ever work, although it worked twice, most of the time only 5 to 6 of them are functioning.
I have no clue what the problem is. The readers are not defect i tested them and my Arduino has enough power. I used the MemoryFree library to determine whether the controller had enough ram.

I would be really glad if somebody could help me.
I attached the circuit and my Code for the arduino. Note that I used an Arduino YUN the one in the image is and Arduino UNO, the only difference is that I had to use other pins for the serial connection.

_9rfid_readers-optimiert.ino (1.51 KB)

rfid.png

Gnd connection is missing for right reader.

I made a circuit myself, it's not that fancy but it's for the YUN.

In the fritzing.. the rigth reader isnt connected to grd. A link on the breadboard is missing

Thank you for the info, but that's not the problem.

I didn't use that image I made my own. I have all 9 readers connected to the right pins.

What is the point of posting the wrong image?

Because my own picture is ugly and I got my inspiration from the one I posted.
Look at my first reply, the circuit is attached to it.