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 swings into action. The device then powers up a small wireless card (which looks like a variant of the very well-documented ESP module), that communicates with his microwave of all things, which in turn alerts him with an audible, spoken alarm that the refrigerator hasn’t closed all the way. It’s all powered with a battery that will eventually need to be recharged.

While there are certainly easier ways to implement an alarm, the use of the spoken alarm is a nice touch for this project, and the power savings that can be realized are not insignificant. There’s also the added benefit that [Javier] can prevent his freezer from frosting over. If you’re in the mood for other great fridge hacks, there are other exciting, novel, and surely one-of-a-kind ways to trick out your refrigerator.

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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, they can also trip accidentally and cost you your steaks. [Derek] whipped up a simple alarm based on current flow to the freezer. A home-brew current transformer made from a split ferrite core and some magnet wire is the sensor, and a couple of op-amps and a 555 timer make up the detection and alarm part. And it’s all junk bin stuff — get a load of that Mallory Sonalert from 1983!

Granted, loss of power on a branch circuit is probably one of the less likely failure modes for a freezer, but the principles are generally applicable and worth knowing. And hats off to [Derek] for eschewing the microcontroller and rolling this old school. Not that there’s anything wrong with IoT fridge and freezer alarms.

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“The Alarm Clock Ate My Duvet Cover, That’s Why I’m Late!”

Some people just won’t wake up. Alarm clocks don’t cut it, flashing lights won’t work, loud music just becomes the soundtrack of an impenetrable dream. Maybe an alarm clock that rudely yanks the covers off the bed will do the trick.

Or not, but [1up Living] decided to give it a go. His mechanism is brutally simple — a large barrel under the foot of the bed around which the warm, cozy bedclothes can wind. An alarm clock is rigged with a switch on the bell to tell an Arduino to wind the drum and expose your sleeping form to the harsh, cold world. To be honest, the fact that this is powered by a 2000-lb winch that would have little trouble dismembering anyone who got caught up in the works is a bit scary. But we understand that the project is not meant to be a practical solution to oversleeping; if it were, [1up Living] might be better off using the winch to pull the bottom sheet to disgorge the sleeper from the bed entirely.

Something gentler to suit your oversleeping needs might be this Neopixel sunrise clock to coax you out of bed naturally.

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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 alarm system is armed, the system begins taking several actions. The stereo system is turned on via IR so that the digital alarm audio file can be played. Lights flash on and off. An IP camera takes several snapshots and emails them to [Nick].

Home Assistant didn’t actually have the ability to send images in an email inline at the time that [Nick] was putting together his system. What did [Nick] do about that? He wrote some code to give it that ability, and submitted it through GitHub. That new code was put into a later version of the program. Ah, the beauty of open source software.

Perhaps the most important part of this project is that there were steps taken to help keep the wife-approval factor of the system on the positive side. For example, he configured one of the scripts so that even if the alarm is tripped multiple times in succession, the alarm won’t play over itself repeatedly.

This isn’t [Nick’s] first time being featured here. Check out another project of his which involves a couple of Pi’s communicating with each other via lasers.

 

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 of an oscilloscope. A ring of 60 LEDs with the piezoelectric sensor form the clock face, all housed in a 3D printed enclosure. A rotary encoder is used to control the clock via an Arduino Uno, though a forthcoming video will delve into the code side of things; [Guichet] has hinted that he’ll share the files once the code has been tidied up a bit.

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Sunrise Alarm Clock with Organic Twist

Most hardware hackers have a clock project or two under their belt. A pretty common modification to a generic clock is to add lights to it, and if the clock has an alarm feature, it’s not too big of a stretch to try to get those lights to simulate a sunrise for a natural, peaceful morning alarm. The problem that a lot of us run across, though, is wiring up enough LEDs with enough diffusion to make the effect work properly and actually get us out of bed without an annoying buzzer.

Luckily for all of us, [jarek319] came up with an elegant and simple solution that should revolutionize all future sunrise alarm clock builds. He found a cheap OLED display and drove it with an LM317 voltage regulator. By driving the ADJ pin on the regulator, he was able to effectively drive the OLED with a makeshift PWM signal. This allows the OLED’s brightness to be controlled. [jarek319] threw some NTP code up on an ESP12E and did a little bit of programming for the alarm, and the problem is solved.

While an OLED is pretty much the perfect solution for a sunrise alarm clock, if you have a problem sourcing one or are just looking for an excuse to use up a strip of addressable LEDs, you can build a sunrise alarm clock out of almost any other light source.

Want To Wake Up In A Ship’s Warp Core? Circadia Sunrise Clock Makes it So

Who among you has difficulty rising in the mornings? Sunrise clocks that simulate a — well, sunrise,  are a gentle means of returning to the waking world. [FlorianH], grappling with this very issue, has built his own impressive sunrise clock he has named Circadia. Some sunrise clocks mate an LED with a dev board and call it a day. This work of hardware art will never be confused for something rudimentary.

Standing at 187cm tall, the 8mm thick PCB frame contains three main sections that plug into each other “like Lego”: the top houses a cleverly designed (and virtually silent) propeller clock and a speaker with a 3D-printed, omni-directional reflector. The midsection is reinforced with an MDF column, around which is wrapped 16 strips of 18 RGB LEDs with a heat-molded sheet of acrylic to diffuse the light, while the bottom section has the mid-woofer, the Raspberry Pi 2 brain, most of the electronics, and three switched power supplies.

Built over two years, the primary feature is a variety of themes — with more being added all the time — ranging from rain forest, to arctic, to the warp core of a starship that will rouse you over the course of a half hour. Circadia can also function as a visualizer during a party, or even a Tetris display (a theme that was designed and tested in an afternoon!). Seeing it in action is a treat:

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