Re: CCTV with Comfort reply

["Andrew Roberts" <andrew@xxxxxxx>]

From: Nigel Orr <Nigel.Orr@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: 13 April 2000 08:50
Subject: Re: [ukha_d] CCTV with Comfort


> At 19:33 12/04/00 +0100, you wrote:
> >A very low cost method is using the relay module with Comfort,
there is a
> >schematic PDF diagram on this page:
http://www.comfort.org.uk/products/rly01.html
(Peripherals, click the house to take you to products)

> I'd seen that- are they particularly special relays or just standard
ones?
> As composite video is only 6MHz bandwidth, I assume it will go through
> standard relays no problem- not sure what the 'video' ones improve on.

The relays are just standard, same type we use on the Comfort PCB (the
telephone relays).
We've had the same set-up working at our office for the last 3 years, the
relays have never glitched.
It never ceases to amaze me just how good yet simple and effective this
setup is. I wouldn't touch another multiplexer or quad again. Why bother
when you can achive intelligent switching of 4 cameras for £33 + vat and a
little 'brain scratching' Comfort programming. We can supply the 8 camera
Comfort config. file to start you off.
http://www.comfort.org.uk/products/rly01.html

> >outputs using colour cameras on just screened alarm cable.
> How long were the cable runs, out of interest?  As I posted a while
back,
> I'd put together a 25-30m run on cat-5 utp cable, with a couple of
phono
> plug connections en route, with no obvious problems, but that was for
a
> mono camera- did you notice any colour problems?

The longest cable runs are about 80 metres, we tried 100m on a drum before
attempting
the installation just to see the possible worst case scenario, if anything
we noticed a slight picture 'softening' at 100m but still acceptable. The
only thing you should NOT do, is try and run two cameras down the same
cable, yes we tried and yes we got 'ghosting'. It became much more a
problem
during darkness. Definately allow for good floodlighting if you are
considering colour cameras at night. They are extremely poor without extra
illumination, but no problem for Comfort of course.

If you want the 8 camera csx file I can send it to you.

Andrew
CHC

>
> Nigel
A very low cost method is using the relay module with Comfort, there is a
schematic PDF diagram on this page:
http://www.comfort.org.uk/products/rly01.html
 (Peripherals, click the house
to take you to products)

We've successfully put 8 cameras through two of these relays connected to 8
outputs using colour cameras on just screened alarm cable. The HCC300 and
301 cameras have built in PIR's and are waterproof.
http://www.comfort.org.uk/products/

The response is programmed so that only one output is active at any time.
We
have the pirs switching on the lights(if dark), announcing the zone
name,switching the relative output to view on the monitor or Scart and
triggerring the Timelapse VCR into emergency record(using another output)).
After movement has ceased, a 20 second timer brings the view back to camera
1 (doorphone). By using flags we can also manually select one of the 8
cameras and the image stays until we switch to auto (flag off).

The picture stability when switched is excellent considering there is no
processing circuitry here.

Using the same responses on the front and back doors means that when you
open the door the lights and cameras switch. Additionally you can do the
same with the garage door remote, open the door when your're down the road,
lights switch on if dark and the door opens and the garage PIR is shunted
to
allow you to drive straight in without creating an alarm or fiddling with
keys at the front door in the rain.


Andrew
CHC

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