Post a New Question | Current Questions | Live Experts
Homework Help: Science: Physics: Shock Sensors
by Jack London
A shock sensor, or vibration detector will actually detect any vibration upon the windows they are placed on, and send a signal to the main control panel to activate an alarm. These are very useful because they attempt to stop anybody actually getting into the house, rather than simply setting off a siren once somebody has already entered. Vibration or movement of the windows activates them, such as that from somebody attempting to smash the window. There is a picture of a shock sensor in the table below.
I am going to place 7 shock sensors on windows throughout the house, on all of the four upstairs windows, and on the kitchen lounge and two upon the large patio windows in the dining room. This is because I feel that shock sensors are very useful since they set off an alarm before entry to the house is gained, and not after somebody is already in. I am not placing shock sensors on the porch windows, or the window of the back door because somebody just knocking on the door could set this off.
PIR detectors (6)
Passive infrared detectors, or movement sensors detect any movement in the room they are placed. An infrared beam is sent into a room, and when this beam is broken, for example by a person walking across the room, then if the system is activated a signal is sent to the main control panel which then contacts the bellbox and sets off a siren.
These should be placed in areas of the house that contain important items that need protection, or items which would be expensive to replace. They should also be placed in the main areas of the house that an intruder is likely to enter into.
They should also be placed so that the infrared beam does not pick up movement through windows, as this could then set off movement outside the house.
I am going to place seven PIR detectors around the house. These will be placed in the hall, lounge and dining room downstairs, but not actually in the kitchen since there are very few objects of importance that could be taken from the kitchen. Upstairs I shall place PIR detectors on the landing, so that anybody venturing upstairs will immediately be detected, and in each of the three bedrooms so the contents of these rooms are protected, and anybody climbing through the windows in these rooms will be detected.
If a family have pets such as dogs or cats in the house when the alarm system is set then these animals by movement could set the system off. The way that I have placed the sensors, the pets could be in the kitchen while the system is on without setting it off, but if the family wished for their pets to have the run of the entire house then a pet guard is available, which stops the infrared beams below a certain height so animals low on the floor cannot be detected.
Internal alarm sirens (2)
An internal alarm siren is basically a siren that can be set up inside the house, so that when the alarm goes off it can be heard clearly inside the house also. These will be activated by a signal from the control panel to activate an alarm.
They could be necessary if the family sets the alarm system whilst sleeping, so that they could definitely hear the alarm if it went off. Also when an intruder enters and the alarm goes off they may not always hear it, but if an intruder hears an extremely loud siren inside the house this may encourage them to leave.
I am going to place two of these in the house, one in the hall downstairs, and one on the landing upstairs. This will ensure that they can be heard from any area in the house.
Rearm facility
Within alarm systems, once the alarm has been activated it is only allowed to sound for twenty minutes, due to regulations and noise pollution. After this time a light on the bellbox will continue to flash. After the siren has stopped, the system is often deactivated, meaning that if a burglar comes back after twenty minutes, they have already gained entry to the house and will be able to quickly get in and take what they want without the system sounding an alarm because it has been deactivated. However it is possible to have a rearm facility on the system, so that once the system has been activated it will rearm itself, and not be deactivated so that if the burglar does come back the alarm will sound again.
This will be set up within the control panel in the house, as I feel that this would be necessary in case of an intruder actually attempting to enter twice.
Panic/personal attack button (2)
A panic button can be placed anywhere in the house, or the remote keypad can be set up so that when two set buttons on the keypad are pressed together a siren will sound. This will work even when the system is deactivated.
I believe that a panic button would be necessary in the house because when people are in the house it's likely that the alarm system wouldn't be activated, meaning that if there was a break in no alarms would go off, so they could press the panic button to set off a siren so that people in the area would know there was a break in.
I am going to have two panic buttons in the house, one in the hall and one on the upstairs landing. This is so that there is one within easy reach whether you are upstairs or downstairs in the house.
RedCARE
There are a number of options instead of RedCARE, and I have outlined some of these before describing RedCARE.
A speech dialler could be used, which is activated by the system alarm going off. A message can be recorded, for example "10 Oak Street is being burgled," and up to five telephone numbers can be dialled to relay the message to. Mr Peterson could set this up to dial the number of a security company, who upon receiving the message would come to the house. However monitoring station and callout fees would have to be paid. A speech dialler would be connected to a telephone line, which means that it does rely 100% upon the telephone line being open. A speech dialler is less reliable than a digital communicator, which also does rely on a telephone link between the alarm and a commercial monitoring station, but what a digital communicator does is send a signal to an alarm receiving centre, who contact a responsible person (key holder.) The key holder could be a security system that will come and check the house for you; this means that callout fees will have to be paid. A digital communicator also does rely upon the telephone line not being cut, which is where RedCARE comes in, which I will explain next.
A digital communicator is activated by a signal from the control panel, or a siren being set off in the house.
I have decided that a digital communicator is necessary because if there is nobody in the area to hear the siren, the burglar could just take whatever he or she wants and leave, with nobody realising or knowing who it was, but with a security company actually coming to check the house the burglar could be stopped in their tracks.
RedCARE will monitor BT telephone lines that are connected to alarm systems. When an alarm is set off, then a signal is sent via the actual RedCARE network within seconds to the monitoring centre. This monitors 24 hours a day, and if the line is cut then this can be instantly detected. Again, monitoring station fees and callout fees are applicable, but this is much more secure than any of the other options, since it will detect line cuts so the house is certain to have somebody checking it in the event of an alarm going off or a te
Homework Help: Science: Physics
For Further Reading
|
