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Saturday, April 22, 2006
Fourmilab: WeatherCam joins FloodCam
After the Great Fourmilab Flood of February 2006, I installed the FloodCam so I (and anybody else who's curious) could keep an eye on the furnace room where the water entered. Due to the shortcomings of the Sony SNC-P5 camera I used (at least for my application), I resolved to try something different the next time, and ended up choosing an
AXIS 206M megapixel network camera, in the hope its manufacturer would get it right. Did they ever! This is one of the cleanest network appliances I have ever encountered. Within five minutes after opening the box, I had live motion video streaming to my Firefox browser window on Linux, all without ever booting Windows, installing any software, or using any Microsoft products. The camera usually obtains an IP address from DHCP when you plug it into a network with the requisite server, but because I preferred to assign it a fixed address on the local LAN (behind the firewall), I set the IP address using arp and ping as described in the manual, which worked the first time. After that I simply pointed my browser at the camera's IP address, set the root password, and was able to immediately view images.
The embedded Web server has a large and well thought out tree of configuration pages, from which I was able to enable automatic time setting with NTP, set the subnet mask for the LAN, and specify the DNS servers. You can set the camera's image properties from the configuration pages, and specify extras such as including the date and time and a camera identifier in the image. Unlike the Sony camera, the AXIS permits image retrieval with a user-specified resolution (not limited to the configured default) with a simple URL. Up to 10 separate users (limited by network bandwidth) can connect and view motion video simultaneously. Separate password protected user accounts can be set up with different privileges, but since the camera is on the LAN and outside access is blocked by the firewall, I specified unrestricted read-only access by any local IP address without a password.
Maximum image resolution is 1280×1024 pixels, with about 12 frames per second of motion video in this mode (up to 30 frames per second in 640×480 and lower resolution). The CMOS image sensor provides 10 lux sensitivity. The manual focus lens has a fixed aperture of f/2.8 and 10 mm focal length, providing a field of view of 45°. Clicking the image above will take you to the Fourmilab Live! page with current images from both the Weather and Flood cameras. If the WeatherCam image is black, it's because it's dark out! You may occasionally catch headlights or taillights on the road at night, but there isn't a lot of traffic around here, especially after dark.
The camera is physically tiny: 100×55×34 mm. It is intended to be permanently mounted, and comes with a mounting stand which includes a ball-joint which permits orienting the camera as desired, including flipping it over for ceiling mounting. Unless I've missed something, there is no socket for mounting on a camera tripod, but if necessary that can be easily kludged by gluing a 1/4 inch nut to the mounting base. At the moment, the WeatherCam is on a jury-rig mounting attached to a ladder with twist ties sitting in front of a south facing window. I will eventually replace this with something more solid, probably the next time I need to use the ladder. This isn't the first time a camera has been mounted on a ladder at Fourmilab!
Posted at
20:36
