# Camera interface

<abstract>
The CM-Home board features the same camera interface as the standard Raspberry Pi 4. Since the HDMI video interface is not available, this article explains how to use the camera over the network.
</abstract>

The MIPI connector for the Raspberry Pi cam is located in the middle of the board closed to the CM4S
socket as shown below:

<img src="./camera_connector.jpg" class="img-responsive">

We chose this position for the camera to facilitate its placement on the front panel of the DIN rail case.

Insert the camera connector with the blue band facing towards the relay, then power on the board and access the Linux prompt via an SSH connection.

Make sure that the auto-detect of the camera is disabled in the file /boot/firmware/config.txt.

	camera_auto_detect=0
	
and that these lines are present:

	dtparam=cam1_reg_gpio
	dtparam=cam1_reg
	dtoverlay=cm-swap-i2c0
	# Raspberry Pi Camera 2.1
	#dtoverlay=imx219,cam1
	# Raspberry Pi Camera 1.3
	dtoverlay=ov5647,cam1  

The last line depends on the model of camera being used.

To check if the camera is visible, type:

	$ libcamera-hello --list-cameras

	Available cameras
	-----------------
	0 : ov5647 [2592x1944 10-bit GBRG] (/base/soc/i2c0mux/i2c@1/ov5647@36)
		Modes: 'SGBRG10_CSI2P' : 640x480 [58.92 fps - (16, 0)/2560x1920 crop]
								 1296x972 [43.25 fps - (0, 0)/2592x1944 crop]
								 1920x1080 [30.62 fps - (348, 434)/1928x1080 crop]
								 2592x1944 [15.63 fps - (0, 0)/2592x1944 crop]

Stream the video captured by the camera on port 8080:

	$ libcamera-vid -t 0 --inline --listen --nopreview --width 1280 --height 720 -o tcp://0.0.0.0:8080

To view the stream from another Raspberry Pi or a Linux PC:

	$ ffplay tcp://cmhome_ip_address:8080

## Links

* [Raspberry documentation on using the camera](https://www.raspberrypi.com/documentation/computers/camera_software.html#rpicam-apps)
* [CM Home schematic](/www/doc_cmhome/cmhome_schematic.pdf)

<hr>

@include='adv_cmpanel'