More about alarm (136)

1-07-2008 | Although this alarm is designed to protect valuables left in a tent, it can also be used as a baggage alarm (either on or in one‘s bags) and...

1-06-2007 | The first two articles in this series show how the microcontroller is capable of ‘playing all alone’ – the only interaction with the outside...

1-07-2006 | This circuit is a laser alarm system like the one we see in various movies. It uses a laser pointer beam to secure your valuables and proper...

1-07-2004 | This circuit was designed to produce an audible alarm when the mains power is interrupted. Such an alarm is essential for anyone whose livel...

1-07-2004 | Sometimes the need arises for a simple, gated, pulsed alarm. The circuit shown here employs just four components and a piezo sounder and is...

1-07-2004 | Most darkness activated alarms employ opamps and some logic ICs. Here, a less expensive approach is shown based on the eternal 555, this tim...

1-02-2004 | Although digital alarm clocks have been around for years, most of today’s off the shelf products suffer from serious design limitations. For...

1-01-2004 | A regular alarm clock, whether stuffed with electronics or of the mechanical variety, will not get you very far if you need to be reminded o...

1-01-2004 | This is a circuit of a simple but effective burglar alarm, which shows the status of each sensor with a separate LED. This allows you to see...

1-12-2003 | This circuit can be built from readily available low-cost components, some of which may even be hiding in your junkbox! The indicated value...