Analog Freezer Alarm
Never come back to a lake in your kitchen
A time-delayed alarm is a useful device that can be used in various scenarios, such as security systems or to remind you to close the freezer properly. The alarm is triggered after a certain amount of time has elapsed, providing a delayed response. In this article, we will discuss the design of a time-delayed alarm using two NE555 timer ICs and some passive components. The NE555 timer IC is a popular integrated circuit that can be used in various applications, including timing and oscillation, both of which will be used in this design.
View inside the box. Buzzer on the left with the oscillator next to it. The time delay circuit on the right.
Components
To build the time-delayed alarm, the following components are required:
- Two NE555 timer ICs
- Resistors
- Capacitors
- 5 V Buzzer
- 9 V battery and battery holder
- Normally open switch
- Perfboard
- Some wire