alarm system

http://www.reachoutmichigan.org/funexperiments/agesubject/lessons/burglar.html
http://www.wikihow.com/Make-a-Door-Alarm
http://www.instructables.com/id/Super-simple-door-alarm/

Videos
http://blip.tv/KipkayVideos/tripwire-bang-alarm-5240694
this one uses a mouse trap and a toy gun bullet caps as the buzzer. the mouse trap is considered the switch. this is an outdoor alarm for the yard. it gives off a loud bang when the enemy walks by. nails are used to hold the gun caps in place. the placement of the garden stakes have to be placed on a walkway. when the alarmed is tripped a metal hinged pulls back. then that releases the trap turning the coil. the trap arm hits the metal caps creating the bang. this was very low tech.

http://blip.tv/KipkayVideos/guard-dog-burglar-alarm-2496758
this one was the most difficult how to alarm system ive seen. he uses a little welding tool. a 50v battery is used as the power source. this is a parallel circuit. the welding tool is used in place of electrical tape. a Duracell procell D battery i think is used. video and audio wires help transfer the sound throughout the house. this one looks more professional by the tools he used. this one is in series with the door bell when it s rung. the door bell helps set off the alarm as well. a mother board has all of the wires connected to it as the brain. everything was pure electrical no wires of anything.


http://blip.tv/howcast-tech-gadgets/how-to-make-a-trip-wire-alarm-1597904
this is a basic trip wire alarm. the materials needed are basic like electrical wire and a battery. He uses aluminum foil on the clothespin as a conductor. all sound devices don't come with wires attached. a complete circuit was made after connecting all of the wires. it is good to test the circuit to see if current flows through. a piece of paper was put inside the clothespin as the thing that sets off the buzzer. when the clothespin is closed it connects the circuit. the wood is used as a conductor also. when tripped the buzzer goes off. the piece of paper inbeyween the clothespin is equivalent to an open circuit.