New Missouri guy looking for a CCTV system for my car

[scorpion 0]

I truely do not know. I am not familiar with your view. I would suggest experimenting with different lens, and see what you get.

[Scruit 0]

Maxima,

 

I have a 4ch DVR in my '96 Maxima that records video only (no audio, but only because I was reusing an old DVR that had no audio). I do audio by having a tape recorder in the cupholder that I can turn on at any time, then I can synch the video/audio by clapping my hands together. Don't laugh, I've done this and it works perfectly just like a clapper board on the movies.

 

I have once camera facing forward that is attached to a cyustom bracket that is sandwiched between the roof and the rear-view-mirror bracket. This keeps the camera tight up behind the mirror so it doesn't get in my way. More on this camera later.

 

I have a rear-facing camera, a cheap $65 bullet, attached to a small bracket that is sandwiched between the rearmost mount of the rear passenger-side grab-handle.

 

I also have a passenger-side A-pillar camera that shows me driving.

 

These cameras are not 'hidden', but they are discreet.

 

The wiring is all RG59 coax that is run under the carpet to the DVR that is under the passenger seat.

 

The DVR is a standard indoor unit that has been modified by using a laptop hard drive (better g-force handling) and uses thick leather straps to mount the drive so provide more vibration resistance.

 

The front-facing camera is important - looks like you are using a camcorder right now... Beware that is you use a standard CCTV camera you will find it cannot handle the dynamic nature of driving a car.

 

The ABSOLUTE MUST-HAVE features for the forward facing camera, in order for it to handle seeing the sun:

1) Auto-iris - otherwise the image will be blinded when the sun comes into shot

2) Outdoor camera - the camera must have an internal IR filter otherwise grass/trees/cars will appear to have strange washed out/yellow colors

 

Also be aware that the camera needs to have a wide enough angle of view to show what is happening to your sides, and the color of traffic lights as you pass.. But when you use a wider angle you will notice that the sun is in shot more (more chances to blind a cheap camera with manaul iris. Also, wider angles will result in the cars in front of you appearing to be much much further away, and the detail level of those cars will be lost. Ie a car that is only 50' away will appear as a tiny blob. I went on yourtube and downloaded a nonch of police dashcam videos, then matched my camera's vew angle to the same.

 

 

 

ANOTHER HUGE HUGE ISSUE....

 

If the DVR/inverter is powered on when the key is in the engine run position then you will find that it will start up as soon as you turnt he key on. If there is enough delay to allow the DVR to start up completely before you start the engine, then you'll find the DVR/inverter could die when you crank the engine. This is a whole area of study for builders of 'Carputers'. When you crank the engien the current draw is so huge that the car's voltage will drop to 10v - which will most likely kill the dvr.

 

The way I fixed this issue was to power DVR from a clean 12v in the maxima (cleaned up using a voltage regulator that is rated for the current draw of the DVR) and then I installed a small 12v 1.2Ah UPS battery ("Tank abttery") with some very heavy duty diodes that allows this "Tank" battery to power the DVR, but stops the voltage from the tank battery trying to help start the car. What happens is the main battery provides 12v (11.6v after the diode) and when the engine cranks the tank battery stays at 12v, allowing the dvr to 'survive the crank'. The tank battery will only power the DVR for a few minutes, but because it only needs to power the DVR during the crank it's fine. Also the tank battery is charged by the car so it's always topped off.

 

 

By modifying a standard DVR (not a mobile DVR) to the same vibration/temperature handling specs as a mobile DVR I've been able to run my 4ch dvr for about a year so far with no problems. DON'T use a desktop HD, they can't handle the vibration and will die after a couple months.

 

 

I ran all the cables under the carpet. There is a white cable conduit that runs the length of the car under the passenger's right foot.

 

 

Finally - you need the DVR to shut down nicely - you can't just shut off power to it or it could lead to a corrupted recording. I achieved this by making a small circuit that has 2 a simple resistor/capacitor timers. When the key is turned on the power controller starts up and provides power to the DVR and to the cameras. When the key is turned off it waits 15 seconds then the first timer shuts down the power to the cameras - this makes the DVR stop recording. Then 15 seconds later the second timer shuts off the power to the DVR.

 

My home-built power controller also has multiple isolated triggers so I can start recording under may different events. For example, the key being turned on will set it recording. Also opening any door will turn do the same, as will hitting or bumping the car (thanks to a vibration switch from a car alarm)

 

 

 

 

Costs:

 

DVR: Free, but a similar entry-level model could be bought today for $300. 60fps is the minumum you need for smooth video shared across 4

channels.

 

DVR modifications: 80Gb Laptop hard drive $150. Mount was made from old leather belt.

 

Front camera: Camera 480tvl CCD with auto iris lens, ebay, $130.

Rear camera: Cheap $65 color bullet

Driver camera: Cheap 2"x2" pinhole/board camera $55

 

Cables/connectors: Total of $75.

 

Power control - home built. Components ran $50, took 40 hours of dev/testing/manufacture. A 'true' mobile DVR will not need this.

[Maxima 0]

Thanks so much. I'm going to PM you since I don't want to alert the local LEO that are watching to too much.