Confuse the burglars with this Mock alarm. It gives an impression that the Home is guarded with a highly sophisticated Security system. The Front panel of the unit fixed in the gate pillar gives that impression, but inside it, there nothing except a flashing circuit. The system automatically becomes active at night and stays on till morning. So no switch is needed. I have fixed it in my gate and many people asked me about its cost and I simply told it is a high cost one.
CD 4060 is used as an LED flasher. It is the binary counter IC with 10 outputs. Each output goes high and stay high a period double than the previous output. Its reset pin determines its activity. When the reset pin12 is high ,IC will be off and when it is low, IC will oscillate with the components C1 and R3. Since low value components are used as C3 and R3, the LEDs flashing will be fast but with a difference in time gap. A buzzer is used which gives feeble beeps to catch attention and making the impression that the system is active. IC CD4060 gives only around 10-20 mA current in its outputs ,so low value series resistors are used for the LEDs. LDR is used to make the system active at sunset.
Design of front panel is very important. It should have a professional touch. Use black acrylic sheet. Drill holes for LEDs, Buzzer and LDR. Letters can be screen printed or use stickers. White letter is preferred. Anyway, making the front panel should be elegant to confuse enough. You can also fix an Old Web cam Lens in the front panel to increase the confusion further. The buzzer will always beep feebly but the person in front of the gate will think that the beeping is due to his presence and message was send. This is sufficient to increase the confusion.