Sentinel explores how our phones turn us into both watchers and the watched. Composed of thousands of automatically captured images, it reveals a quiet, relentless self-surveillance. I told the machine to spy on me, then spoke back through code, organizing chaos with color and structure. Algorithms act as brushes, images as pigments, forming panels grouped by season, day, or hour, stressing the constancy of surveillance, a double dialogue in a form of post-photography native to our era.