Rongge

This is a Password based Door locking system with GSM. The project mainly consisting of PIC microcontroller (16F877), 16x2 LCD Display, GSM Modem, Keypad and misc.(Relay, Crystal oscillator, power supply which is not shown in circuit diagram) The program is compiled using PICC Compiler and simulated on Proteus 8. All Header and simulation files are given at the bottom of this post. The default password is set as 123. This project can be implemented anywhere where, higher security is required. If the user enters correct password, that is “123”, the relay gets active and opens the door. If an un-authorised person trying to access the system and enters the password incorrectly three times, the system gets locked and alert the owner by sms using Gsm modem. Once the system gets locked a count down timer will appear on lcd and you have to wait that predetermined time period. Read More.....

Because I’m old school, I wanted to build a Garage Door Closing circuit without relying on integrated configurations (555 timer etc) to keep it simplistic. The circuit closes the garage door after two minutes with C3 and four minutes with the addition of C2. The timer relay is surprisingly accurate (+/- five seconds). Another feature is to ensure that the garage door actually did close, such as if it’s stopped mid-operation by the user. S3 (magnetic N.C.) is located at the garage door and activates the circuit when the garage door opens. RL1 is the reset timer. It’s maintained in the “on” position for two minutes by C3 while the trigger capacitor, C4, is charged. RL2 is the conduit, directing C4 to either RL3 or R1 to ground when off. Purpose of R1 is to prevent arching across contacts and a fast discharge. RL3’s contacts are connected to the Garage Door’s Momentary Switch and is sustained “on”  for a half second by C5. When C3 discharges to the cutoff voltage of RL1, it turns off ...