Jim's Depository

this code is not written

I’ve been using USB cameras on tiny repurposed routers, beagle bones, and raspberry pis for some time. I’d like to deploy more cameras, but I am on a tight power budget where every watt matters and my DC power controller that allocates the power is out of ports and I don’t really want to build another one.

Enter “power over ethernet” (PoE) cameras. These hang on an ethernet cable and receive their power from that cable so I only have to run out a cat5 and I’m set. I can buy ethernet switches with PoE and control which devices are powered at any given time.

Danger: most lower cost “smart” switches allow you to control the port power, but only through their silly web interfaces, they don’t allow it over SNMP until you pay for an enterprise device. It appears SMC has a model that will allow SNMP control.

In the made up land of retail pricing, PoE cameras are a little pricey compared to their less capable friends. Fortunately China is a really big place and lots of things are made and sold there. I found 720P PoE cameras for $25 each delivered half a planet away.

Good: They have pretty good picture quality, aluminum “weather proof” enclosures, IR lights for night time, and you can order with four different focal lengths. H.264 over rstp.

Bad: They really sad documentation, on a mini-CD, like I own a tray loading CD drive. Are hardwired to boot on despite documentation that gives a different address, have an open telnet port with a root account backdoor with fixed password, respond with a web interface only in Chinese that doesn’t let you configure the camera in Chrome and Safari. Chrome will offer to guess at translations and turn the text back near English.

That “Bad” entry took me about 3 hours to work out. I do not have the root password, but apparently some tech support responses give it to you.

Proceeding onward, I got Microsoft to give me a demo copy of Windows 8.1 and spun that up in a VirtualBox. If you hit the camera with Internet Explorer, enable Active-X downloads from unknown and untrusted developers and basically give total control of your machine over to unabashedly anonymous people, then you get a web interface that can be used in English and can tell the camera to use DHCP or some static address of your choosing. (I use DHCP for everything and then tell my DHCP server to give a static address to certain MACs.)

The rstp streams can be found at rtsp://camera.example.com:554/user=ACCOUNT&password=PASSWORD&channel=1&stream=0.sdp?real_stream--rtp-caching=100 for the high res stream, and stream=1 for the low res.

Unresolved: I’d like to find a URL to pull a single frame. Perhaps if I figure out how to query the ONVIF interface enough it will tell me.

Further thoughts: It is hard to fathom how someone can sell me a computer, with a camera for $25, in a nice aluminum case and ship it half a planet on demand. Because I need individual control of the power on the switch ports, I’m spending almost that much on the hole in the switch!