Hi
I have been working with Android for a while now, so I can defanitely do this job. Since you "just" want a timer, there will be a lot of focus on the design. Of course, I'll try to follow Google's material design guidelines and make it as simple and sleek as possible.
Now, I'm still pretty young and new to freelancer.com, so if the app ends up not as wanted, you don't have to pay for it. As for now, I only have one app in the Play Store, afgange+. It's a public transportation app, though it only works in Denmark, so not the best example.
Best regards
Edi Begovic