Simple Key-Operated Gate Locking System / Mains Box Heat Monitor / Faulty Car Indicator Alarm / TACHOMETER

Simple Key-Operated Gate Locking System
This simple key-operated gate locking system allows only those persons who know the preset code to open the gate. The code is to be entered from the keypad within the preset time to operate the motor fitted in the gate. If anyone trying to open the gate presses a wrong key in the keypad, the system is disabled and, at the same time, sounds an alarm to alert you of an unauthorized entry.

Mains Box Heat Monitor
This simple circuit monitors the mains distribution box constantly and sounds an alarm when it senses a high temperature due to overheating, helping to prevent disasters caused by any sparking in the mains box due to short circuits. It also automatically switches on a bright white LED when the power fails. The LED gives ample light to check the mains box wiring or fuses in darkness. The circuit beeps once when power fails and again when power resumes.

Faulty Car Indicator Alarm
Before taking a turn, either left or right, car drivers need to switch on the car turn indicator lamps so that the approaching vehicle drivers can take precaution accordingly. An accident is likely to occur in case your car turn indicator lamps fail to glow due to some reason or the other. Here is a circuit that sounds an alarm if your turn indicator lamps don’t glow, helping you to safeguard against any accident.