Hi. How tall is this robot from ground to top of chassis?

Hello and how are you. I am interested in getting this for my son. I have a couple of questions. The first is why are you using analog rotation sensors instead of a 4 axis plateform sensor/board ? Is the arduino a uno type ? does it have a wireless controller to it ? Does it have any type of motive or object avoidance sensor or will it just bang into things ?

THanks

Sean