ACCESS CONTROL SYSTEM

      System has a keypad with which any 3 or 4 digit number can be entered. The number is settable by the user. When the number entered matches with the preset number a ttl level high going signal is received upto 1.5 to 5 seconds. With this signal a latch can be operated through a relay which will open the door. In case if somebody tamperes the unit it will sound a audible alarm. There should be a gap of 15 seconds between 2 entries. If wrong code is entered 4 times the alarm will sound for 4 minutes.