You will want to choose version 1.0 or 2.0 based on your needs.
1.0 Arduino_Hex - runs on the robots 2560 micro-controller, this version does not contain code for the pixy.
2.0 Arduino_Hex_Pixy_Walking_Version_R2 - runs on the robots 2560 micro-controller and contains all the code for the pixy integration. If you choose this version you will want to also grab PixyProgramHeightWidth.
PixyProgramHeightWidth - loaded to the micro-controller (arduino nano) that reads the pixy data and sends it to the robots 2560.
PS2X_lib - Library for PS2 Controller
Updated HardwareSerial - Arduino-0021 - Updated HardwareSerial library for Arduino 0021 > You will want to overwrite the two HardwareSerial files located at: C:\Users\xxxx\Desktop\arduino-0021\hardware\arduino\cores\arduino With the files in the updated HardwareSerial folder in this repository.
Arduino Enviroment 0021 to compile and upload the code in this repository; you will want the same. You can get it at the following URL: https://www.arduino.cc/en/Main/OldSoftwareReleases#00xx