Because internet CCTV cameras are intelligent, as opposed to the “dumb” traditional CCTV cameras, you can use them to see your property from wherever you are in the world, over the internet. That, however, is just the start. By joining these cameras to simple alarm and control circuits, they can be used to monitor and control doors. In part one of this two-part series, I will show you how the monitoring side of the equation works.
Seeing your home, business or family from the other side of the world is amazing enough, but wireless internet CCTV cameras can do so much more than even this impressive feat. Most of the best of this type of camera will have a digital input/output port, or I/O port, that allows the camera to be connected to electrical circuits. The two input connectors on the port can be used to monitor an alarm circuit and trigger an alarm as I will explain.
The input connectors can be wired to each end of a so-called alarm circuit that in reality is nothing more than an unbroken loop of low-voltage wire, connected to, say, a pair of magnetic door contacts. These are a standard part of any alarm system, but for those of you who have not come across them, you basically get two magnets, with plastic mounts. One of them has connectors for the two wires of the alarm circuit. You screw this one with the wires to the door frame, and the other one to the opening door so that they are lined up very close to each other when the door is closed, which keeps the circuit unbroken. This is known as a “normally closed” or “NC” circuit, because in its normal state, the circuit is complete or closed. When the door is opened, the magnetic contacts separate and the circuit is broken.
The wireless internet CCTV camera will detect when the circuit is broken because there will be a change in voltage at the input connectors and the camera is programmed to raise the alarm when this happens. So, when the door is opened your camera can send an immediate message across the internet to a central computer. This computer is programmed to send a text message to your mobile phone, and perhaps an email too – all within seconds of the door being opened. Of course, if you want this great feature without “getting your hands dirty”, you will need a specialist “internet CCTV” company that can provide you with a camera pack ready-configured to work with your alarm circuit, so you can just plug it in.
We looked at how your wireless internet CCTV camera can monitor the area in front of an external door, and raise an alert when someone approaches the door. In this final part of the series we are going to look at the next step in the process; how to use your camera to unlock the door.
You may remember from part one that most good quality internet CCTV cameras have a digital input/output port, or I/O port. This is simply a series of connectors that allow the camera to be attached to electrical circuits. I have shown you in part one how the two input connectors on the port can be used for monitoring an alarm circuit and raising an alert. In a similar way, the two output connectors can be used to switch electrical equipment. Your camera can be configured so that a current is sent to the output connectors under certain circumstances. This gets very interesting, because unbelievably you can use the camera to actually open the door! So how can a wireless CCTV camera actually open a front door? I will explain how in the next few sections.
The first piece of equipment you will need is an electronic door release, which you fit to the door frame. This is a common piece of equipment in home and business security systems and can be obtained inexpensively by searching for “electronic door release” on the internet. The door release is fitted to the door frame so that the catch on the door lock fits into it. The door lock is untouched and the door can be unlocked with a key as usual, but the electronic door release can also open the door. It does this by freeing the catch from the door frame without unlocking the lock, when a current is sent along the attached wires.
The next step is simply to run the wires from the door release mechanism to the output connectors on the internet CCTV camera’s I/O port. The camera has to be programmed so that it will accept an “open door” text message from your mobile phone or from a web page, and send a current to release the door. Of course, you may be happy enough fitting the door release mechanism, but programming the camera to work with it is a specialist task. I always recommend getting in touch with an “internet CCTV” provider for a ready-programmed camera that you simply plug in, so you get this great feature without needing any technical knowledge.
Once you have everything connected, here is how it all works in practice. Let’s say you get a text message alert from the camera to tell you that someone is at the door, and you know it’s about the time your son gets home from school. You log in using your mobile phone or PC and see a live picture of your son standing outside the front door, unable to get in because he’s forgotten his key. You can simply send a text message from your phone to a central number, with your password, user name and a simple command such as “open front door”. A central computer program gets your text message and processes it, checking your credentials. Then, the system sends a message across the internet to your internet CCTV camera, and the camera then sends a current to the door release mechanism, which opens the door for your son, all within a few seconds!
New applications for wireless internet CCTV such as door monitoring and control bring the technology to a different level when compared to traditional CCTV. This is yet another reason why these intelligent digital cameras are fast replacing dumb analogue cameras the world over.