Security Systems
There is a door. It could be to a business, it could be to a home, it could be to a funeral home. For my purpose here, it actually is to a funeral home. I don't figure they would even have a security system, but concentrate on The Door rather than where it is.
How do you know if you can open this door without an alarm going off?
Firstly, you would check to see if there's a sticker on the door, right, promoting some security company?
Suppose there is: how do you open The Door without it going off?
Suppose there isn't: how can you tell if there is an alarm?
Also: Does anyone happen to know a lot about security systems? Enough to know what the most common ones are?
easy, open the door and retreat to a good hiding spot where you'll wait and see if anyone shows up. if nobody shows up, either head inside or come back on another night and follow through.
p.s. you may have to enter the establishment to trigger any alarms before you go hide.
The most common sensor on a door alarm is a magnetic reed switch. It'll be on the inside 99.9% of the time. It consists of a sensor mounted mounted next to the edge of the door, and a small magnet on the door. This will look like 2 little white boxes, usually in the upper corner of the door. When the magnet attached to the door is moved away from the sensor, that's what triggers the alarm, silent or otherwise usually by causing an electrical circuit to fall open.
I personally haven't played with something like this, but I believe it would be possible to trick the sensor by using a powerful enough electromagnet While opening the door, and then just bypass the sensor from inside, either with a smaller fixed magnet, or by fiddling with the wires. Another idea would be to get inside earlier and affix a small powerful magnet to the sensor box preferably out of sight, so that when you open the door and pull the magnet on the door away from the sensor the sensor is still effected by the field of the smaller magnet.
I've never tried this, but I assume with some trial and error it might be viable, although I highly recommend against breaking into anywhere. If they have a security system, getting past the door will be the least of your problems.
wait, does this involve necrophilia?
Well, the first and most obvious question is: why do I have to go through THAT door? Most basic security systems focus on electronic sensors on doors and windows. Someone opens or disturbs one while the system's active and loud noises begin. If it was super high tech, you'd also have video cameras, heat/motion detectors, etc to deal with inside.
My first thought would be to find the least obtrusive way in. Roof? Upper floors? etc.
If you must use only that door, it becomes a little more difficult. Is there setup time? Could you scout the location to see what happens at closing? Since most businesses have very public-facing well-lit entries, they focus on using physical deterrents (locks/gates/etc) to prevent break-ins from the front, while the alarms tend to go on the unseen entries.