Building a website for the archeology department is a real engineering project. It requires domain knowledge, requirements gathering, specification, working with stakeholders, iterative design, deployment, and consciousness of maintainability.

"Something with drones" is not a Software Engineering project. Writing a poem about drones is enough. On the other hand, if you can show future employers that you solved AI or Big Data as a senior project, the road ahead will be paved with yellow bricks.

The critical thing is to show your ability to execute and part of a portfolio is to provide a familiar context in which to discuss engineering decisions as engineering decisions.

Don't get me wrong, some students will have really cool ideas for their senior project. Many of them will have been thinking about it for a long time. A few of them will just be the sort of person who comes up with cool ideas. It's a bit late to try and become either type.

Good luck.