how do i make a bedroom door alarm

[computron4]

i am thinking of getting the siren alarm from beginner kit and the flashing led light can you help me figure a way to connect them and put then on the same power supply i also need to figure out how to make a trigger that will trigger them both i have an idea but id liek to have soem other ideas im so confused  ??? ??? ??? ??? ??? ??? ??? ??? ???

[steven]

i hope this helps the simplest bedroom door alarm  i used a battery, or you can use a transformer ,and some metal contact s, both on you door and door frame and a dc buzzer now when your door is opened the metal contacts on the door contact the metal contacts on  the frame thus setting off the buzzer . make the contacts flexible so you door can open wider  or space them apart more , for any other ideas that may help look at the circuit for ufo detecter in the high voltage stuff section, once the buzzer in that is set off it will stay on untill you switch it off