Arduino -> RaspberryPi -> Webserver

Hi

I have a project I have been looking in to a bit. I would like to create a timer on a Raspberrypi with java, pritty simple. It updates time every secound on the screen.
Now the part I would like to have help with, if i connect a Arduino to the raspberry with serial or something. Is it then possible to stop and start the clock with for instans a button on the Arduino?

Or is it some other way that is better to do this. In the end I would like to pressent a timer on a webpage och controll it with a physical button.

This particular project, I'd just use the Pi.

an esp-01 can present a web page and read a button