In this Instructable We are going to see the making of simple Door Bell for our rooms,this project is simplest one even made by beginners very well and very cheap .this project costs $1-$2.
Most of them want privacy on their room, this Door Bell may use to avoid the interruption of others. Simply make this project and fix it on your room, this may help to ask the permission to entering by others.
This Door Bell may also used by main Door Bell of the house.
This Door Bell circuit contains two normal NPN transistors (BC 547) and a musical transistor BT 66 T19L.This circuit consumes 3-4.5V.The amount of volume of the Door Bell is increased by increasing the Voltage level.