PIR Motion Detectors Wired to DVR Alarm - Which PIRs Work?

[Fiona 0]

I have a Dahua DVR with NC and NO Alarm inputs. The PIRs/alarms trigger Presets on the PTZ Camera. So far so good. The problem is this: Dahua seem to specify 12 volt inputs for the Alarm on the back of the DVR. (As opposed to simple dry contacts. NO - NC and Ground.) But most of the PIRs that operate at 12 volts seem to produce a 28 volt Output for the Alarm. Am I misunderstanding how the Alarm input works? Does the Dahua Alarm take higher voltage inputs than they seem to specify? Is there anyone there who can explain in plain English the method of connecting a wired PIR to the DVR? Are there any Motion Detectors that are commonly used on DVR/Alarm/Preset scenarios? I am thinking of the GE Sentrol 6187CTX which is an outdoor unit. The Forum mentions the Crow Daredevil which appears to be superceded. I would greatly appreciate any boffins who can answer this.

Edited March 31, 2010 by Guest

[tomcctv 190]

I have a Dahua DVR with NC and NO Alarm imputs. The PIRs/alarms trigger Presets on the PTZ Camera. So far so good. The problem is this: Dahua seem to specify 12 volt inputs for the Alarm on the back of the DVR. But most of the PIRs that operate at 12 volts seem to produce a 28 volt Output for the Alarm. Am I misunderstanding how the Alarm input works? Does the Dahua Alarm take higher voltage inputs than they seem to specify? Is there anyone there who can explain in plain English the method of connecting a wired PIR to the DVR? Are there any Motion Detectors that are commonly used on DVR/Alarm/Preset scenarios? I am thinking of the GE Sentrol 6187CTX which is an outdoor unit. I would greatly appreciate any boffins who can answer this.

 

you should only be using n/o n/c alarm contacts from the back of your unit (12v is max you can put though) the pir is powered external to dvr.

[Fiona 0]

Tom, thanks for replying. Does that mean the PIR or external device only creates a closed circuit (or open circuit) when connected to the NO or NC inputs on the DVR? I understand that this makes sense but what is the 12 volts that Dahua refers to relating to? It sounds like Dahua want a 12 volt input from the PIR. I understand that the PIR is externally powered by, say, 12 volts. And do you know what the 28 volts that is often mentioned on Motion Detector specifications mean? I appreciate you sharing your technical expertise with a raw yet keenly enthusiastic CCTV novice.

 

Wait a minute - hold your horses. I have just had an epiphany! Does the PIR contain a Relay that typically handles up to 28 volts? So that the Relay alone could create the Normally Open or Normally Closed circuit with the contacts at the back of the DVR.

 

If so, why does Dahua specify 12 volts?

[tomcctv 190]

Tom, thanks for replying. Does that mean the PIR or external device only creates a closed circuit (or open circuit) when connected to the NO or NC inputs on the DVR? I understand that this makes sense but what is the 12 volts that Dahua refers to relating to? It sounds like Dahua want a 12 volt input from the PIR. I understand that the PIR is externally powered by, say, 12 volts. And do you know what the 28 volts that is often mentioned on Motion Detector specifications mean? I appreciate you sharing your technical expertise with a raw yet keenly enthusiastic CCTV novice.

 

Wait a minute - hold your horses. I have just had an epiphany! Does the PIR contain a Relay that typically handles up to 28 volts? So that the Relay alone could create the Normally Open or Normally Closed circuit with the contacts at the back of the DVR.

 

If so, why does Dahua specify 12 volts?

forget about voltage. connect your pir to 12 volt then n/o or n/c contactor back to dvrs n/o n/c alarm inputs

[Fiona 0]

Okay Tom, I've forgotten all about it. Thanks for that. I will follow your advice as soon as I can lay my hands on the correct PIR/Dual Tech Motion Sensor. Elsewhere in the Forum, Members mention the Crow Daredevil outdoor motion detector which now seems to be out of production.

 

Are there any Industry Standard PIR/Dual Techs that are routinely used by CCTV Aficionados?

[scorpion 0]

Set up your dvr so that when you put a wire across the contacts on the back of you DVR then when you remove the wire (an open circuit) it will trigger the recording.

 

Why?

 

If they cut the wire then you have an open circuit, and you have a DVR trigger to record even if they get around the motion detector.

 

Motions detectors:

 

There are too many variables and you should seek a professional.

 

Are you using PIRs inside, or outside? If you use them outside then be prepared to have false positives, such as wild animals triggering the DVR. If you have the detectors under a covered area then you mitigate movement from trees, and birds on the wire (this is assuming you have a long throw PIR).

 

Question:

How far out do you want to detect motion with the PIR?

 

Perhaps it may be better to use a photo beams.

http://www.optexamerica.com/productpage.aspx?l1=2&l2=7&id=6

 

The advantage is that you have less false triggers. If an animal were to walk through it may be tall enough to trigger the lower beam but not large enough to trigger the upper beam. If a person walks through then they will trigger the upper, and lower beams, and you will not get a trigger off of every animal, or moving tree limb, and such.

 

In regards to motion detectors:

 

There are long throw detectors, but they have a narrow path. There are wide beam motion detectors, but they do not reach out very far. You will need to know the distance that you are working with, and you need to select the perfect detector to match your environment.

 

There are battery operated motion detectors where "security is NOT of the essence". These battery operated detectors can be placed anywhere with hook and loop (velcro), or can be mounted with screws, or you can use silicone sealant to mount them in a unique way.

 

There are also motion detectors that have x10 (communication over the power line) that can trigger many devices at once. You can trigger your DVR, outdoor lighting, and anything else that you may need. You can place a receiver in to an electrical outlet, and it can receive signals from the motion detector, and then send "an alert" over the power line. You can have the alert received in the room where the DVR is located to trigger recording, and you can replace a light switch with an X10 light switch, and this will allow the outdoor lights to come on with the "alert".

 

X10 has a reputation for "not working", and this is false. This is based on poor design by installers. I have been on many sites to replace X10 with another technology, and I show them the problem, and how to correct the problem, and then make the system work like it is supposed too work.

 

There are devices that solve multi branch power line communication problems, and there are filters to remove noise from the electrical system, and some other "pro installer" tricks of the trade that I will keep to myself.

 

What do you want your system to do?

Is this a residential system, or a commmercial system?

Is security of the essence?

How much are you protecting? Spend about 10% of that value as a baseline, and spend more when you elevate the threat level.

 

If you are spending less then 10% of the total value then you have nothing to protect, or you are in the hobbyist level, and your threat level is very low.

 

If you are on a budget then think of the big picture down the road.

If you plan it right, and you plan a good "infrastructure" then you can put in a backbone system, and just a small investment will get you going, and you can add to your system as you need.

 

I have seen where people spend the least amount of money, but later when they up the performance level of the system they actually have to replace the everything, and start all over again! Not a good investment to begin with!

 

Think smart, and plan everything out. Make a silly wish list, and dream of what you may want it to do. Now get into a system that will allow you to be flexible.

 

If you buy the cheapest alarm panel, and later you need to add more devices then it would be great to add wireless motion detectors, and window contacts, but if the panel was so cheap that it did not have the wireless communication as part of the system then you saved money, but then again you wasted it. You may as well buy a panel that has mutli zone add on, wireless communication, and X10 (or related technology), and other options. You can wire a front door, and a back door, and have only one motion detector, but when you go to upgrade you are good to go, and you can create the perfect system.

 

All I am trying to say is "do not box yourself in" based on a small budget. You may spend a small amount more then you would prefer, but then you save more money down the road!

 

What do you think?

[Fiona 0]

Wow! What a thoughful, well-considered reply. You have cleary pointed out the parameters to the problem. I couldn't agree more about your comment regarding underfunding a CCTV installation. I have started a domestic installation with the best intentions. A Hitachi VK-S654 inside a Speed Dome. I researched the DVR problem and came up with Dahua which alone captures 52% of the Chinese market. http://www.dahuasecurity.com

 

The installation is in crime-ridden Melbourne Australia. (I see you are in Melbourne Florida. What are the chances?) I live in a new suburb inundated with Heroin addicts and wanna-be home invaders. I have almost a nightly security issue. I am trying to set up the First Speed Dome to jump to Presets over a 270 degree periphery of my house. I realise I will have to get at least a second equivalent dome. And you raised some very good points about making any Motion Detector perform additional functions which I didn't consider.

 

There are some trees that may interfere with a PIR in the wind. I thought of using narrow "curtain" type PIRs to focus the instrument at perhaps a street corner frequented by louts or at a park in front of the house. As the camera would only have an image of under 60 degrees it stands to reason that 180 degree Motion Detectors would trigger over a wide area and the PTZ would jump to a Preset and therefore stand a 2 in 3 chance of catching no Event.

 

You seem to be saying that in Security we need to keep our options open. So that we don't have to go back to rip out everything only to reinvest and do it all over. I couldn't agree more. And I guess that is why I am putting some effort into the PIR/Beam/Dual Tech Motion Detector issue. What if I put in the wrong PIRs only to discover all the points you raised then had to pull them out.

 

So then, External PIRs covering Hot Spots in a typical suburban scenario. Some trees, birds, cats etc. Do the Pet Immune PIRs resist the detection of branches swaying in the wind? (I have tried to trim back all such branches as a preulde to installing Motion Detectors.)

 

I have some comment to make myself about brand-name PIRs that appear generic and are marketed under different names and dramatically different prices. But for the moment I remain only a keen novice listening to the words of wisdom from the CCTV Forum Experts.

 

Once again, thanks so much for such a detailed reply. Thankyou.

[scorpion 0]

I was unaware that you would be using the PIR to control PTZ position.

 

Using PIRs will be a bad choice in general.

 

I only say this because my belief is you have no "control" over the territory that you are watching. You say street corner, and I am thinking of an open area where people are allowed to travel, and not a security zone where only "authorized personnel" are allowed.

 

Question:

Will the PTZ be controlled by different PIR? In other words if there is alot of "traffic" in mutiple zones will the PTZ be watching a "tennis game" going back, and forth?

 

I can see why you have to use PIR as you do not "own" the street corner, and therfore you cannot install beam device on this location, and run wire back to your property.

 

In regards to the high crime area I would want to know if you have iron bars on the windows, or if you plan on installing bars on your windows.

 

I would want to look at the "whole" picture. I would use the iron bars, and thorny shrubbery to force a person to walk in a direction that I create. In other words a sidewald with thorny bushes on either side forces them down the sidewalk. What a perfect place for a "man trap" and a good facial shot, and this would be a great place to put a camera.

 

Why are you interested in watching property that is not yours? I cannot understand the extra expense? I can see recording this area as an approach point. I would not use a PTZ on this area. I would use a 220X zoom camera. A PTZ would be great if you did remote view.

 

The last post sounded more of a "professional" surveillance system rather then a simple home solution.

 

You need to think about high crime. You need to think about cutting the power to get to the building without an alarm.

 

You need to think of serious battery back up, or solar power, or your own battery bank, and an inverter.

 

Will your system be monitored by an alarm monitoring company for police dispatch?

 

Will you be hiring security services to respond (rental cops with yellow lights rather then red, and blue) to an alert.

 

I would want to look at this for the big picture also.

 

What kind of "mean" shubbery can you plant to deter them from coming on your property, and make them go to a property that is much easier to get in to?

 

Shrubbery is prettier then concertina wire!

 

Can you install a KOI pond? It creates a water barrier, or a way to redirect a person to a camera.

 

What do you think?

[Fiona 0]

You have raised so many good points that I just hadn't considered. (And I thought I had it all figured out.) The reason I am concerned about the public area is that it is a "hot zone" where drug addicts actually inject heroin in public. Little children toddle past on scooters and bikes with trainer wheels oblivious to the scene. In fact I think most of the neighbourhood is oblivious to the events. I am only just realising that a PTZ with a decent zoom lens can see things that most people will never see. Last week I captured a perpetrator attacking a neighbour then attempt to grab an iPhone. Gangs of young wanna-be teenagers roam the public areas at night thinking they are unwatched and vandalise property. All of this was a surprise to me and I guess it only serves to make me more apprehensive.

 

However, even one prominent PTZ Speed Dome can change public behaviour. I have noticed a wariness from criminal types as they slowly become aware of "the camera". Clean living folk and older citizens are appearing more now in the park and I have encouraged other home owners to make efforts at reclaiming this new suburb.

 

The land authority has created an ambience to this new suburb and a caveat restricts front fencing. I didn't want to put bars on windows but that may now be inevitable. The use of thorny hedges is a darned good idea. Thanks for that.

 

But again, you have clearly thought out so much of the problem that I didn't see. In my niave approach, I had thought that a Speed Dome with narrow beam PIRs would have animated the PTZ 24-7 so that criminals would have been dissuaded. And as you would know, an external corner mount PTZ has a vast field-of-view. The PIRs would to some extent automate the camera and the surveillance which would be a good first step. I am pretty sure that I am going to just run wiring to robust PIRs to monitor the "hot zones." Then I'll probably run beam alarms along the rear fencing.

 

Thanks again for the clarity of your ideas.

[tomcctv 190]

You have raised so many good points that I just hadn't considered. (And I thought I had it all figured out.) The reason I am concerned about the public area is that it is a "hot zone" where drug addicts actually inject heroin in public. Little children toddle past on scooters and bikes with trainer wheels oblivious to the scene. In fact I think most of the neighbourhood is oblivious to the events. I am only just realising that a PTZ with a decent zoom lens can see things that most people will never see. Last week I captured a perpetrator attacking a neighbour then attempt to grab an iPhone. Gangs of young wanna-be teenagers roam the public areas at night thinking they are unwatched and vandalise property. All of this was a surprise to me and I guess it only serves to make me more apprehensive.

 

However, even one prominent PTZ Speed Dome can change public behaviour. I have noticed a wariness from criminal types as they slowly become aware of "the camera". Clean living folk and older citizens are appearing more now in the park and I have encouraged other home owners to make efforts at reclaiming this new suburb.

 

The land authority has created an ambience to this new suburb and a caveat restricts front fencing. I didn't want to put bars on windows but that may now be inevitable. The use of thorny hedges is a darned good idea. Thanks for that.

 

But again, you have clearly thought out so much of the problem that I didn't see. In my niave approach, I had thought that a Speed Dome with narrow beam PIRs would have animated the PTZ 24-7 so that criminals would have been dissuaded. And as you would know, an external corner mount PTZ has a vast field-of-view. The PIRs would to some extent automate the camera and the surveillance which would be a good first step. I am pretty sure that I am going to just run wiring to robust PIRs to monitor the "hot zones." Then I'll probably run beam alarms along the rear fencing.

 

Thanks again for the clarity of your ideas.

 

Hi fiona i have just pm you a ptz to play with . so you can see please press preset when you log of from it.

[tesc_cctvpro 0]

Unfortunately, these sort of issues and more are what most DIY consumers don't realize.

 

If the security threat is such that your life, property, safety of loved ones is threatened, please get a professional security consultant to design and install your CCTV system. We cannot teach you on here all that a professional consultant would know.

 

Firstly CCTV is a monitoring function, it is only one part of a security system. Unless you have dedicated person's watching the cameras, cctv will not detect anything or anyone. The PTZ and zoom cameras you describe are known as active surveillance devices, and are less effective than static cameras in detecting events. The PTZ will be useful for investigating an event, but who will do the investigating, and how will they be alerted to an event.

 

video motion detection technology is a form of video intelligence, it is not free of false alarms . Just as beams and security PIR's are not free of false alarms either. All of these technologies are at best configured to achieve the lowest rate of false alarms.

 

On a DVR - Dahua, you can select specific areas of an image to include or exclude from motion detection,You could actually design a virtual tripwire to activate recording.

 

However, all of this is designed to create an alarm, a percentage of which will be false, the alarm alerts someone????? Who is that someone? Are they constantly monitoring the system? You can set the Dahua DVR to email you when an event occurrs. Where will you be when this happens?

 

CCTV is then employed to investigate the alarm, to verify if it is a valid alarm, and then to initiate a response.

 

These are all considerations you need to consider before discussing hardware. Who will be monitoring the security system, who will validate and investigate the alerts, who will respond to the alerts, Why, What, When, Where, How.

 

CCTV is not a security system, it is part of a security system which performs the monitoring and investigation functions of a security system