Hi,
i am working on a similar project and using the PIC16F877A
for wireless communication, there is RS232 wireless chip, I havent tried it yet but i know a guy used it for a project and says its easy to use
for sensors and ideas check this website:
How to Build a Robot Tutorial - Society of Robots
and if you using the PIC16F877
this website is a good start:
https://www.mikroe.com/en/books/picbasicbook/06.htm
you can use proximity sensor to detect objects
now i am trying to find a speed sensor to put on my project,,