I want to shoot a timelapse sequence of a sunrise using my Canon 200D. It does support a timelapse video mode, but the settings are quite limited - I can either set everything manually, set auto-exposure for the first shot only or set auto-exposure for all shots. If I try shooting in the first two exposure modes I get the obvious problem of the scene getting too bright as the sun comes out in the sky. If I set the camera to auto-exposure on every shot I get uneven lighting as the exposure meter doesn't guarantee a smooth gradient.
I've read online that the solution to this issue is to use a bulb intervalometer, which essentially let's you fine tune how quickly the exposure changes between shots. However devices that support this are quite costly (300$+) and I'd rather not invest in them right now. Is it possible to achieve the same effect by connecting a phone or a laptop to the camera and using a piece of third-party software?