https://www.tomshardware.com/how-to/use-raspberry-pi-as-pc-webcam
Direct USB Connection (Pi Zero / Zero W only): This is probably the best connection. To make this work, add the text dtoverlay=dwc2 to the bottom of /boot/config.txt and add modules-load=dwc2,g_ether after the word rootwait in /boot/cmdline.text. Install Bonjour Printer Services if you’re using Windows. Your Pi Zero must be connected to a USB port on your PC via the micro USB port that’s labeled “USB” on the Pi itself. Make sure to enable Internet sharing on your PC (see below).
http://www.davidhunt.ie/raspberry-pi-zero-with-pi-camera-as-usb-webcam/ https://www.pcwelt.de/a/webcam-mit-raspberry-zero-pi-w-einrichten,3448168
https://blog.gbaman.info/?tag=g_mass_storage https://learn.adafruit.com/turning-your-raspberry-pi-zero-into-a-usb-gadget/ethernet-gadget https://gist.github.com/gbaman https://gist.github.com/gbaman/50b6cca61dd1c3f88f41
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Add dtoverlay=dwc2
in a new line at /boot/config.txt
add modules-load=dwc2,g_webcam,libcomposite
after the word rootwait in /boot/cmdline.txt
<code>
______________________________________ |O :::::::::::::::::::::::::::::::: O| |-------- | |SDCard | | |-------- ______ ___ ___ | |O_________| HDMI |____|USB|___|USB|__O| ^ /|\ | use this | ____________/
<code>