Burglar alarm using parallel port!?

i need to create a burglar alarm using parallel port with software interfacing using Turbo C codes imported into Java (JNI)





the problem is that i cant figure out how to do the hardware part!


can anyone suggest me any online resource for that?





i have to either use the keypad security system model or use a sensor attached to the door that goes on whenever the door is opened. I also need to know which pins of parport to connect the hardware to and what signal should i tell the program to look for..





please help fast!

Burglar alarm using parallel port!?
Wouldn't it be simpler with USB.


You can much easily find components for usb and it is easier to program.


http://www.delcom-eng.com/downloads/USBP...


http://jusb.sourceforge.net/
Reply:You can use a parallel port easily. For the keypad part, use an Intel 8279 - it's a keyboard controller. (It's old technology - circa 1978 - but it's still the easiest way to interface a keypad.)





For the sensor, hang a 1k resistor on the 5 volt line and connect the sensor between the other end of the resistor and ground. Connect the junction of the sensor and the resistor to a pin on a parallel port. (I'd use an isolation resistor and a buffer chip to keep transients from blowing the port.) Then you watch for a transition on that port pin - whether it goes from 0 to 1 or 1 to 0 depends on whether the sensor is open or closed when the door is closed. They come either way.