Brigadoon - An Occasional Corner on the Internet
Sky Camera (Introduction)
Designed by Mark Little
The Raspberry Pi comes equipped as standard with an interface for a high definition camera board. A 15cm ribbon cable attaches the camera module to the Raspberry Pi board.
For the camera to function, an operating system module must be enabled. This can be easily done using the raspi-config program on the Raspberry Pi.
To enable the camera, run "sudo raspi-config", the select "5 Emable Camera". Select "<Enable>" when asked "enable support for Raspberry Pi camera?".
Access to the camera can be obtained via the Multi-Media Abstraction Layer (MMAL) or the Video for Linux (V4L) APIs. Alternatively there are libraries such as Picamera Python, and others available on-line.
Raspberry Pi Camera
Ethernet/WiFi Video Camera
If you are not using a Raspbberry Pi, or you want to mount the camera outside in a day/night situation, it may be simplier to use a Commercial Off The Shelf (COTS) camera that connects to your network using an Internet cable or WiFi.
Many of these camera come with Infra-Red illumination so that the scene can still be viewed at night. This is especially important when the camera is being used for security surveillance purposes.
The operating instructions for the different brands vary, so reading the instruction is a must.
When setting up cameras, it is especially important that the location of the Sun is taken into account for all times of the day and over all seasons. If this is not done and the sunlight falls directly into the camera, it will, at best, wash out the image and, at worst, damage the sensor. This is especially important if the camera is being used to monitor the state of the sky as the camera is likely to be pointing upwards and more likely to get direct sunlight into the lens.
If using the camera for surveillance purposes, the camera should be set up to automatically turn the Infra-Red LEDs off and on depending on the other illumination.
Sky Camera are video cameras that have been set up to monitor the state of the sky. There are two types of cameras that are considered in this project.
(1) The camera module that connects directly onto the Raspberry Pi circuit board via a ribbon cable.
(2) The fully assembled camera module that can connect to a network either via an Ethernet cable or via a WiFi link. This sort of camera can be controlled by most Linux computers using the script provided. A full size image of the Brigadoon Sky Camera can be found here.
The objective of this project is to provide a means by each either of these two types of camera can be used to generate sky images capable of being published in the Internet.
USB Video Camera
Any USB camera that the operating system recognises and control via a device driver (typically "/dev/video0" can be used by this script.
However, at this stage, the script is not able to control any LEDS associated with this device. This will need to be done by another program..