Kiwi

Regarding the power carried by the Cat5, there is nothing magic here, you still have to consider wire resistance. Google tells me it is 3.05 ohms per 100 ft per conductor. So 350'/100' x 2(directions) x 3.05/(2 cond each direction) = 10.7 ohms. At 2 A that's a drop of 21.3 V, so you will have to start with 12 + 21.3 = 33.13 V to get an even 12 out the other end. Note that the 24 VAC quoted is 5 VA, or 5/24 = .2 A You really should provide local power or run a heavier gauge just for the power conductors.

"VGA" technically means 640 x 480 x 60 Hz (31.5 kHz.) Some cheaper extensions that cut corners with wire size and shielding will only meet this spec. Let us know how it works.

Should not be any problem with the coax. I can certainly see how it could be an issue with multiple baluns however, something I've never considered before.

The alarm output connection triggering a beeper via a common 555 timer circuit would work just fine. You should be able to buy a suitable kit at Radio Shack.

It's an output and a very low-current one at that. It provides feedback to the driving circuit as to the effectiveness of the driving current at moving the iris. The term "brake" which we often see used is not an accurate description of the function.

I have tried to design the opposite circuit - to operate a manual motor-driven iris from the camera's DC signal. The lens is a Computar 8-80 that I picked up cheap since it was lacking the DC iris. It didn't work as the motor couldn't move the iris fast enough to respond before the camera integrated the error to the maximum value. You are correct - there is almost no technical information or standards available for this fairly common device. What you are trying to do won't work either as there is no positional feedback from the DC iris to tell you when you have matched the voltage demand. The camera knows this instantly by the resulting exposure level. The DC iris has two coils, one to move the iris and the other to provide velocity feedback. The moving part of the iris has a magnet and is normally held closed by a light spring. The driving coil opens the iris against the spring somewhat proportional to current supplied, while the other generates a small current proportional to the iris velocity. If you apply 0 - 30 mA to the drive connections you can open the iris, however you will find it very hard if not impossible to obtain any stable intermediate position. With a suitable series resistor to supply the minimum required current you can leave it fully open permanently. Have fun!

"Losses" in BNC's are normally more useful in applications involving far higher frequencies than a mere RS-170C video signal. Don't worry about it.

The FTP option might work just fine if the sensitivity is set low enough to trigger all the time, but of course the DVR was not designed to host a webcam. if you have a computer running in the house buy a capture card and loop the video thru the DVR to it. Run a webcam application such as Willing Webcam (the best I've found). With a http server running and DDNS client (if needed) you're done.

I need some feedback on how to improve these images. The lenses are the 4mm ones supplied by Arecont. I would probably want to move closer to 6 to 8mm if I have to change the lenses. Daytime 1920 x 1200 http://tinyurl.com/3ybev7 Nighttime 1280 x 1024 http://tinyurl.com/2wjpot

Geez, what an unpleasant situation to say the least! If your child is aware of and able to react to and report the potential danger I would imagine that's a major step to being safe during the day. I'm not sure why he would be standing in the clearing at night in any case, since he probably couldn't see either! Perhaps at night it boils down to the same sort of security you would need for any sort of intruder. I'm thinking an IR beam surrounding your property to let you know immediately if there is an intrusion. I have a wireless doorbell and sensor on my back gate 120' away and it gives me a sense of security far beyond what I expected since I'm always home and nobody coming through the gate has any idea I know it was just opened. There is a device available that combines a cheap digital camera with a motion detector, designed to photograph wildlife. Perhaps that would work nailed to a tree to get the evidence you need? 300 ft just seems like a long way to get an image good enough for reliable motion detection.

You can view mine here: http://tinyurl.com/3olxez Have you looked at the IQeye?

The 12V output in a PC is well-protected against current overloads, is well-regulated, and often has plenty of excess capacity - those items are unlikely to be issues. The two risks I can see with sharing the supply are: a) If the camera video is connected to a card in the computer you may create a ground loop between the video shield and the 12V return, which is grounded to the computer at one end and in many cases connected to the video shield within the camera. This may not be an issue with newer cameras that take either 12vdc or 24vac. b) Any wire leaving the computer box is a potential antenna for RF noise going either in or out. A ferrite bead would take care of that however.

Somewhere I saw a reference to this upgrade recently that indicated that it does work.

Perhaps you can get them to leave their address and phone number as well. Won't a domestic camcorder do what you want? CCTV can get pretty expensive. A night or two spend in the back seat with a baseball bat might be a lot cheaper.

Measuring power supply output voltage without a load is meaningless and you have simply now discovered why.

And yet dozens if not hundreds of other companies with similarly high-tech products are perfectly happy allowing customers to upgrade their own firmware with the exact same risks.

I agree - firmware upgrades should be made available on the Arecont website. The last one I got for my 3130 took way too much arm twisting and it's clear that the problem I complained of is improved but still not entirely resolved.

With multiple failures I would be looking at causes outside of the disk itself. I personally hardly ever see disk failures that can't be explained. If it's surface damage (head crash) it was probably due to an impact to the disk or external vibration while running. If it's an electronic failure I would be looking at power supply and filtering issues, and of course cooling. Another more unusual possibility is excessive mechanical stress to the disk due to installation in a poorly-designed bracket that microscopically bends or stretches the housing when the screws are tightened.

My Avtech 782 might have the same power board. It converts 19V from the power pack to the 3.3/5/12 etc. I replaced the small fan with a 4" blower and all has been well for months despite the increased load. Can you not identify and replace the blown semiconductor(s)? It certainly should have been designed well enough to protect itself in event of a simple current overload.

Radar? As it happens I was involved in a minor role in the original design of that product perhaps 15+ years ago when it had a different owner, and as pointed out on the current owner's (Rapidscan) website it most definitely uses low-level X-rays. Invasion of privacy was the biggest impediment to sales, aside from the US$100k price tag. One of our staff was even fired for scanning an attractive but uninformed female temp worker. While we owned the product we never sold a single unit, but one was lent to a Mexican prison to scan the visitors. It did have a software mask for covering the naughtiest bits but no-one ever looked good. http://www.rapiscan.com/sec1000.html

1. perhaps there's an FTP equivalent to tinyURL.com 2. did you check the relevant boxes under "alarm" from Video Server E?

She might be talking to her husband about a certain "adjustment" after the Monica incident.

I really have no idea but I would be surprised if they did not design the board in-house as there would be little added-value left in the product. Plus you don't see other products with the same interface other than the relabeled brands (CP and Gadspot, if I recall.) Perhaps someone else knows...

I would expect the application of an IR source to be no different than to a normal CCTV camera. It's a matter of matching it to the lens FOV and distance to the subject. At least on the 3130 you have a number of options regarding exposure time v.s. frame rate. However there doesn't seem to be a (documented) trigger off the camera for switching on the IR so it will need to be done separately.

It looks to me like you measured the voltage at the camera with the camera disconnected? Otherwise I don't see how you could get close to 12V, there must be some voltage drop with the camera load. If you use the remaining 3 pairs for power, give each pair a plus and minus.