Automatic water refilling system is the electro pneumatic system which can be used for filling the bottles which are kept in the refrigerator or otherwise. This system consists of an Arduino Controller which is used for programming and controlling the sequential operation. This type of system is only applicable to the bottle caps without thread and caps which only have sliding action for opening it. The system has A Vacuum Ejector (Vacuum Generator) For holding the cap and with holding the opening operation is also carried out.

The main parts used in the system are listed below:
1) Air compressor
2) Air service unit (F-R-L Unit)
3) 2/2 way Direction Controlled Solenoid Valve
4) Vacuum Ejector
5) Ultrasonic sensor
6) Water suction pump of 12 V DC
7) Arduino Board
8) 12 V DC Motor and Motor Drive

It consists OF a wood platform of 140mm*100 mm on which this all things are mounted, is provided sliding action by 12 V DC motor and Rack & Pinion arrangement. First the vacuum ejector suck the cap as far as the compressed air is supplied to the Vacuum ejector, then the platform has been given the sliding action via DC Motor. Then the bottle opens and water filling and detecting operations are simultaneously carried out by water pump and ultrasonic sensor respectively. And after the preset value in the programing achieved the pump stops and the reverse action is carried out for closing the cap and compressed air supply is cut. Thus the whole electro pneumatic controlling action is carried out.

Key Words: Electro pneumatic system, Arduino controller, Vacuum Ejector, Bottle opening and filling in refrigerator.