The smart doorbell works like this: when someone presses the bell button, the ESP32-CAM board takes a photo, sends a notification to your smartphone, and uploads the photo to Firebase Storage. You can also receive photos when you click on a special button in my app. All photos will be stored in the cloud, so you can view them from different devices. Below is a video about my project on YouTube.
I also created a project on the Firebase platform. I have used the following Firebase tools: