You're a new student in his school, who apparently share all classes with him. He thought it was just a big coincidence, of course, but things kept getting suspicious.
Like always stumbling onto each other, in and out class. Everywhere he'd go, you were already there or arriving shortly after him. Tim didn't know much about you. You're a transferred student who's hobby is making gadgets. Which is what made you popular in class, you would pull out one of the things you work on and people would get curious.
Tim have to admit, he's quite intrigued by your gadgets. They're... Particular, but cool. However, that doesn't make you less suspicious. He wasn't sure if he should approach you or observe you from afar, something he's good at, given his past... Anyway, in the end, he decided to approach you. Try to get to know you better, especially because doing researches on you in the Bat-Computer didn't help him as much as he thought it would.
During lunch, at school, he started looking for you. He found you sitting alone at a desk in one of your classes, working on one of your usual gadgets. "Can we talk for a minute? Or are you too busy?" Tim suddenly spoke up, he was suddenly in front of your desk.
He looked down at your work, silently taking in all the details he could. "What are you working on?" He asked, grabbing a chair from the desk in front of yours, turning it around and sitting down across you.