The standard Raspberry Pi models only offer a single MIPI CSI-2 interface, and it becomes a handicap in building a multi-camera application. However, single as the Pi camera interface seems, it’s still possible to add multiple cameras to the Raspberry Pi, and even synchronize them. The following chapters will show you how to achieve that.
Use a Raspberry Pi Compute Module
This is the most no-brainer answer: if your Pi only has one camera port, then get a Pi with multiple camera ports. Unlike the consumer-level Raspberry Pi A, B, and Zero series, the Raspberry Pi Compute Module is an SoM (System on a Module) without IO peripherals. You can connect the Compute Module to an IO Board where you will be able to use two cameras on.
Use USB webcams
USB camera is another simple solution. You have enough USB ports on the Pi to multiple webcams, because if you don’t, you can easily expand that with a USB hub. Even with a single USB port, it’s also feasible to use a USB stereo camera on it.
Use Arducam Multi-camera Adapter
Arducam offers multi-camera adapters to accommodate up to 4 camera modules on a single Raspberry Pi and switch between them quickly. The HAT-style quadruple adapter fits well with the Raspberry Pi A&B series, and the double adapter is perfect for the Pi Zero. You will read more about it in the following chapters.
User Arducam Synchronized Stereo Camera HAT
If you are not satisfied with the Arducam multi-camera adapter and its camera-switching mechanism, the Arducam Synchronized Stereo Camera HAT is the choice. It’s a magic product that deceives the dual-camera setup as a single camera module connected and accepted by the Raspberry Pi, so the two cameras are fully synchronized.