Proximity Door Bell..!!!!!
1. IR Sensor
2. 9 volt battery with battery cap
4. X-meter(length) of wire
1. Connect the Gnd and Vcc of IR Sensor with Negative terminal and Positive terminal of the battery.
2. Connect a wire through output terminal(3rd Pin of the IR Sensor) and Negative terminal of the battery and Connect to the +ve and -ve of the Buzzer.(The Length of the wire here depends on your Door width.
3. Use Cardboards and make a box like structure now Attach it to the Door.