| The new breed of CCTV cameras known as wireless | | | | damage the camera. Fortunately most PIR sensors |
| internet CCTV cameras or IP cameras is totally | | | | have a fairly standard output signal, and cameras are |
| digital, more like a computer than a traditional camera. | | | | designed to work with the majority of them. Choose |
| This new type of camera detects changes in the | | | | a good quality sensor that can be adjusted for |
| digital image that its sensor "sees" to decide whether | | | | sensitivity and set to exclude the movement of small |
| something has moved within the picture. This method | | | | objects such as pets. To make fitting easier, go for |
| of detecting movement can be improved upon by | | | | one with a built-in battery. Although it is possible in |
| adding a passive infra-red (PIR) sensor to the | | | | theory to power the sensor from the camera, in |
| camera, as this article explains. | | | | practice it is tricky to get enough power to the |
| There is a limitation to using internet CCTV cameras | | | | sensor and often easier to go for the battery option. |
| to detect movement. These cameras determine | | | | Next we will look at how the sensor is attached to |
| whether movement has occurred within their field of | | | | the camera. |
| view by examining changes in the digital images that | | | | Take a look at your camera's manual to find the pair |
| the camera's optical sensor produces. One problem | | | | of input connectors within the connector block. Then, |
| with this approach is that changes in the digital image | | | | you simply take the two wires from the sensor and |
| may have been caused by something other than a | | | | connect them to the input connectors of the |
| person moving around. For example, if a street light | | | | camera, making sure you connect positive and |
| suddenly comes on outside a room where the | | | | negative wires to the appropriate connectors in |
| camera is located, there will be a big change in the | | | | accordance with the manual It is no more difficult |
| digital image because it will be suddenly brighter. The | | | | than wiring a plug. Next, attach the sensor to the wall |
| camera will notice this change and will raise a motion | | | | or ceiling so it is "looking" at the same view as the |
| detection alert - a false alarm in this case. There are | | | | camera. This means that when the sensor detects |
| several ways to resolve this problem, for example by | | | | movement, the camera will be recording that |
| using sophisticated image processing software in the | | | | movement. We also need to make a small change in |
| camera or on a central computer so that people are | | | | the camera, as the next section explains. |
| "recognised" as people and an image-wide change in | | | | The internet CCTV camera itself needs to be |
| light level is ignored. A simpler solution, however, is to | | | | configured so that it will raise the alert and record |
| use a PIR sensor. | | | | images not when the camera itself detects |
| A top quality wireless internet CCTV camera will | | | | movement, but rather when its input port receives a |
| usually have a small block of connectors known as an | | | | signal from the PIR sensor. It is usually a case of |
| I/O or input/output port, which has several purposes. | | | | changing a single setting on the camera's event |
| The port is just a series of holes where wires can be | | | | set-up page, so that any motion detection "trigger" is |
| attached and tightened with a screw. The pair of | | | | ignored; rather it will be a signal from the input port |
| connectors known as the input connectors are the | | | | that causes the camera to raise an alert. This is |
| ones used if you want to connect a sensor such as a | | | | usually a simple change but will vary according to the |
| PIR sensor. The inputs are used because the sensor | | | | camera model, so please consult the manual for |
| is sending a signal into the camera, as opposed to the | | | | details. |
| camera sending a signal outwards. | | | | By using a standard PIR sensor with your wireless |
| You need to choose a PIR sensor that will work with | | | | internet CCTV camera in this way, your camera will |
| the camera. The camera's ports will be able to accept | | | | be able to detect movement more accurately and |
| incoming signals of a certain wattage and voltage, | | | | consequently the number of false alarms will be |
| and attaching anything to the input ports that sends | | | | greatly reduced. |
| in electrical signals above the allowed range could | | | | |