Laser Home Security System | Science Project | Newbr br School Projectbr br Use Components-br br 1- Two BC547 Transistorbr br 2- Two 1k Resistancebr br 3- LDR Sensorbr br 4- LEDbr br 5- Buzzerbr br 6- Battery Capbr br 7-9 volt Batterybr br 8- Laser Lightbr br 9- Mirrorbr br Science Project,br Science Model,br Science Experiment,br Science,br science project,