Category Archives: alarm

Fridge Alarm Speaks, and Saves Power & Food

One of the most power-hungry devices in our homes, besides the air conditioner or heater, is our refrigerator and freezer. It’s especially so if the door doesn’t close all the way or the magnetic seal doesn’t seat properly. [Javier] took to solving a recurring problem with his personal fridge by attaching an alarm to the door to make sure that it doesn’t consume any more power than it absolutely needs.

At its core the device is straightforward. A micro switch powers a small microcontroller only when the door is open. If the door is open for too long, the microcontroller …read more

Continue reading

Posted in alarm, door, ESP, ESP8266, microcontroller, Microcontrollers, refrigerator, seal, wireless | Leave a comment

Junkbox Freezer Alarm Keeps Steaks Safe

A fully stocked freezer can be a blessing, but it’s also a disaster waiting to happen. Depending on your tastes, there could be hundreds of dollars worth of food in there, and the only thing between it and the landfill is an uninterrupted supply of electricity. Keep the freezer in an out-of-the-way spot and your food is at even greater risk.

Mitigating that risk is the job of this junkbox power failure alarm. [Derek]’s freezer is in the garage, where GFCI outlets are mandated by code. We’ve covered circuit protection before, including GFCIs, and while they can save a life, …read more

Continue reading

Posted in 555, alarm, comparator, current transformer, ferrite, freezer, fridge, GFCI, GFI, home hacks, magnet wire, peak detector, refrrigerator | Leave a comment

Keep the Burglars Away With Some Pi

Ten years ago, we never imagined we would be able to ward off burglars with Pi. However, that is exactly what [Nick] is doing with his Raspberry Pi home security system.

We like how, instead of using a standard siren, [Nick] utilized his existing stereo system to play a custom audio file that he created. (Oh the possibilities!) How many off the shelf alarm systems can you do that with?

The Pi is the brains of the operation, running an open source software program called Home Assistant. If any of the Z-Wave sensors in his house are triggered while the …read more

Continue reading

Posted in alarm, burglar alarm, home hacks, home security, home-assistant, Raspberry Pi, security | Leave a comment

How Good Is Your Aim First Thing In The Morning?

For the less than highly-driven individuals out there — and even some that are — sometimes, waking up is hard to do, and the temptation to smash the snooze button is difficult to resist. If you want to force your mind to immediately focus on waking up, this Nerf target alarm clock might get you up on time.

Not content to make a simple target, [Christopher Guichet] built an entire clock for the project. The crux of the sensor is a piezoelectric crystal which registers the dart impacts, and [Guichet]’s informative style explains how the sensor works with the help …read more

Continue reading

Posted in alarm, android, Arduino Uno, clock, clock hacks, leds, nerf, target | Leave a comment