Do university accept a Mechatronics Engineer undergraduate to do Masters in computer science? I finished my undergraduate studies in Mechatronics Engineering and have a low CGPA. The main reason is that I'd been developing web application and doing small projects (creating robots). I have interested in doing Masters in computer science, because it would help me to get better understanding and I have a huge interest in artificial intelligence systems. Do Universities in USA accept undergraduates, who don't have CS and have less CGPA? Please share your ideas. It will, really, help me a lot.
This will depend entirely on the University. My University, for example, does not look at whether you have a degree in CS, but does look at factors they feel influence whether you are likely to complete your Master's in CS. Those include your GPA, if you've completed certain core upper division CS and lower division math classes, and your GRE scores. Each year they accept the  students most likely to complete the degree.

Ultimately, you will need to contact the CS department of universities you are interested in, and ask them their policy. You will probably find a low GPA is more of a hindrance than the lack of CS degree. When I was looking at US universities for my MS, I didn't find a single one that said my undergrad degree (in math, not CS) would be a problem.