Using USB Cameras with Arduino

I have a fairly fundamental question about USB cameras…

I would like to be able to take still pictures with USB cameras using a microcontroller and I am looking at the way this problem is solved on forums like this to try to understand how to do it. I understand that USB cameras would act as a slave device so I would need my device to act as a host (with an Arduino this might be done with a USB shield).

However, I have read several posts which say that not all USB cameras are the same and that one would need to create a driver for each one individually. I don’t understand this because I can plug any USB camera into ‘normal’ USB hosts such as Mac, PC, Raspberry Pi, mobile phones, etc. and they all seem to work fine - they don’t appear to need special drivers.

So what’s going on here? Do these hosts have thousands of drivers pre-installed? Or are all USB cameras essentially the same?

BTW, I am asking this question because I want to understand what is going on for a separate project - I know that Arduinos would probably be too short of memory, etc. to make a video camera on an Arduino a realistic prospect.

connect the camera module to the arduino directly. the circuit should have 4 pins; 5V, D+, D-, GND. Try connecting accordingly and do your homework.

To my knowledge that is just not possible. The Arduino doesn't have enough ram to even take a still with a 2 MP USB camera or even smaller. Also jayyou, it is not that simple, the Arduino uses the ATMEGA 328 (generally) and it has no USB options.
Using a Shield would give you the connection but your still left with way too small processing power.

Not using a Webcam but being an Arduino project you could maybe use something like the ESP32-CAM board (examples here).

Another option would be to use the Raspberry Pi Zero with it’s camera as it can stream video. Check Google but an example I found here.