All the cool phones now are doing facial recognition. While that sounds like a big job, you can add face detection and recognition easily to your projects if you can support the OpenCV library. [LinuxHint] has a great tutorial that steps you from the basics of OpenCV to actually acquiring and identifying faces. It is aimed at Ubuntu users, but the code would apply to any OpenCV-supported platform. You can also see a less detailed tutorial to learn more about installing OpenCV on the Pi Zero from [DanishMalhotra].
Of course, any facial recognition system is going to need a camera. The nice thing about the first tutorial is that it assumes you know nothing about OpenCV, so it covers the basics on up to using the face-related libraries.
