Hello Danny.

See just qualifying any of the engineering entrance exams in the country doesnt provide u a seat in any of the college to pursue ur btech career. For getting mechatronics u should be scoring a min score to get a seat in the Vellore campus. U might score somewhat less for the CHENNAI campus. U can also opt for management quota is u are lagging a bit score to get a seat.

Hope u got ur point. Ask if any query 

Good luck