Door intrusion and water level sensors

[fubuaks]

I m doing this project in which the unit (microcontroller,pcb) is placed inside a cabinet.
I need a sensor for detecting any attempt of theft, as in, if anybody opens the door of the cabinet a command is send to the microcontroller.
Another sensor is required for detecting the water level, if it goes low below a certain level, the uc gets interrupted.

What kind of sensors i shud go for and where can i find theory about them?
If anybody could provide help on these two things.....

[Binu]

For sensing the doors you can use magnetic switches, which are cheap and easy to interface.
For water level sensing you can use metal probes.
Search the forum for more details.

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