Dual DVR setup

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I have a CPCam CPD576W 9channel standalone DVR. It's an entry-level system that is only capable of 25fps total.

 

It records 24x7 by splitting the 25fps across all 9 cameras, resulting in something like 3fps per camera and a 10-day history from a 500GB HD. I've tried exclusively motion detect in the past but found it to be unreliable because of trees and bushes blowing in the wind, most of them in an area of the screen I can't exclude from motion detect - plus I've missed a couple of interesting events because of motion detect, and one time had a guy in my driveweay and lost footage of most of the event because he stood still!

 

I *do* use motion detect to adjust the allocation of framerate. When there is motion the logic is that non-motion cameras get 1fps, and the rest of the fps is shared between the cameras that DO see motion. So if someone walks past one camera then I get that event is about 17fps (25fps - 8fps for non-motion cameras = 17fps), which is fine. 2 cameras seeing motion will get 25-7=18, shared equally = 9fps each.

 

This works fine for me - I'm not trying to catch someone shoplifting or cheating at cards - just want evidence in case of a burglary etc.

 

 

The problem I noted is that when there is motion one one or more cameras, therefore the non-motion cameras drop to 1fps, a car driving fast enough could pass under the license plate camera and not be seen - ie the license plate could pass into shot and out again within one second. It's happened a couple of times now where I've missed the plate completely.

 

To solve this issue I took an older 4ch 30fps DVR and installed it alonside the 9ch DVR. I took the loop output from the primary 9ch DVR ("Argus") of the 4 most important cameras and setup the secondary 4ch DVR ("Argito") to record 24x7 also. Argito has a 160GB hard drive, so I expect 3 days of history from it. I can extend that if I go on vacation.

 

Argito gives me two benefits:

 

1) Faster framerate (7.5fps) that is unaffected by motion on the other cameras, making it impossible to drive fast enough to beat the license plate camera through speed alone. Previously a car doing 10 mph would likely be missed - now the car would have to be going freeway speeds to run the risk of being missed. It's a 150' loose gravel driveway so although 10mph feels pretty fast I've seen people go faster, but nobody is gonna get up to 75!

 

2) It's a completely seperate DVR that provides a backup of the most important channels - the onse that can help me identify the perptrator. (3 cams detailed enough to recognize faces over each door, and the license plate camera). I've had a hard drive failure on Argus and went at least a day with no CCTV without knowing it. Now I'd have to lose both DVRs before I lost video. I have tested and both DVRs will record independently even if the other ia turned off - ie the primary DVR doesn't need to be powered up or recording for the loop out to work.

 

 

We'll see if the better framerate allows me to improve my license plate capture rate...