Wednesday, 1 November 2017

Case Study: WiFi Surveillance Cameras on Wireless Mesh

I have been waiting for a FREE weekend for a long time to install Surveillance Cameras in our  Apartment complex.After many "working' weekends, I have got FREE weekend in last week. Having known the differences between Analog and IP Cameras, I definitely want to install IP Cameras. But it involves a lot of wiring and again as a WiFi guy, I explored  WiFi Cameras. We did a site-survey and finally concluded that we need 8 cameras.


Personally I love to install  networking devices at customer's places. Fortunately I have got multiple chances right from college days where I tested my master's thesis on a live long-distance WiFi Link testbed in Kanpur and also got an opportunity to do a site-survey and install a relatively big Outdoor-WiFi testbed in Detroit, USA.  Now its time to install Wireless Cameras.

Cameras

On some research on Internet, we have got this wonderful Wireless Surveillance  System from Zmodo.  It is a set of 8 WiFi cameras (4 Indoor and 4 Outdoor)  and NVR (which includes hard-disk too). It is available on Amazon.  https://www.amazon.com/Zmodo-Channel-Wireless-Security-Available/dp/B01N5Y7UI5/ref=sr_1_1_sspa?ie=UTF8&qid=1509528326&sr=8-1-spons&keywords=Zmodo+8+Channel+1080p+HDMI&psc=1 . One of my friends, Kiran Reddy shipped this product to me from USA.





Range Issues and Mesh Network 

Given the area of the premises, I know, one Router cannot cover the entire premises.  But again, I don't want to use any Cables. So, an alternative is to use a Mesh Network as backhaul to which all the WiFi cameras will connect to. Fortunately it is not an issue for me. I have developed multiple mesh solutions in the past and BANA is the most economical solution. So, BANA is a trivial choice.  Please check: http://www.nearhop.com

 Here is the cute little Router sleeping like lizard on the ceiling.





RF-Survey

We have already decided on placement of Cameras. We have to decide on the placement of Routers. I thought to use 3 Routers to cover the entire premises. But after a little effort on Site-Survey, I find that two Routers could cover the entire premises. One Root device and one Repeater are sufficient. We have connected the NVR to the Root. The distance between Root and Repeater is around 25 meters with a big cement wall 

Powering the Cameras and Routers

You can't avoid one thing, whether your surveillance system is wired or wireless. That is Power supply. So we have added some plug points and it needs some wiring. But it is very little and not a big issue. 

So, now we have the power supply, Cameras  and Routers. All set. I have configured the Routers and Cameras before installing them. 

All the cameras are live in the first attempt itself. Four cameras have connected to Root and the other four connected with the Repeater.

 I have waited for 4 days to see if things are stable. The system seems to be running smoothly and quality is good. I will try to post some snapshots in some other post.

Quality

As per Zmodo, each camera needs a bandwidth of 1Mbps. So for 8 cameras we need 8Mbps of effective throughput in the Mesh network. 8Mbps of throughput in a mesh network is not a big deal for this mesh network.This Mesh network easily pulls-off this and quality is really good.  I will try to post the videos very soon.

Hardware and Softwae

The mesh network in this case is running on very ordinary Routers with a single 2.4Ghz Radio configured in 20Mhz (Do we really get 40Mhz channels in 2.4Ghz). It has 64MB of RAM and runs on MediaTek's processor MT7620N. Firmware is based on heavily modified OpenWRT and uses a proprietary Mesh Network protocol.

Learning

Point#1, To deploy  WiFi cameras on large scale, one needs to do an RF-survey. Point#2, you don't need a high-end expensive mesh products even for bandwidth sensitive applications like video streaming.


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