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.

21 thoughts on “Fridge Alarm Speaks, And Saves Power & Food

  1. Why o why are there so many projects regarding fridge alarms…

    Here are some proper solutions:
    https://www.amazon.com/door-closers/b?node=511282

    But for the tinkerer (hobbyist, maker or whatever term is hip these days) it would be more fun to mount a spring or rubber band in an appropriate place? Perhaps more fun would be a weight suspended through a pull construction connected to the ceiling and the fridge door.

    Because only then the door would close (by itself) which is the whole goal. Okay, you all have a point when you say that that solution would not look as pretty and it would never pass the Wife Acceptancy Factor (WAF) criteria, but it can work for years and years, does not need any power or maintenance and also works when you wifi changes it’s settings or when you are on holiday and thieves forget to close you fridge door. Sometimes modern technology is just too complicated for the problem we are trying to solve.

    Honey… did you charge the fridge door alarm last week… there is a pool of water in the kitchen?!?

    But seriously now, the project itself contains a lot of interesting technology, for instance an MP3 player in the microwave, I did not see that one coming!

    1. Tell me about it. This is a fundamental misapplication. “[Javier] took to solving a recurring problem” – No he didn’t. Javier plastered over the problem and instead of fixing the cause implemented yet another annoying gadget that could break.

      If the magnetic seal doesn’t seat properly every single time the door comes close to being closed, chances are the seal is stuffed anyway and you could save quite a bit of money by fixing it.

      1. If the fridge is well designed – when it’s level the door closes on its own.

        Ours had a built in two stage alert if you leave it open to long as well.

        But that is of little use if something stops the door from closing like trying to squeeze too much into the fridge :o and you head promptly out the door before the alert triggers so having a text message sent could have it’s benefits.

        Now have it powered of an energy harvesting sytem like a peltier on the evaporator coil ( or just fit it all in the interior light well and power it of the supply to the light and use that to trigger it as well.

  2. Hint hint industry. There are minivan doors that self close and such. Refrigerators have online screens and such. Need I say more. Hackers you know what to do.

    One simple thing to check. The magnetic gasket contacts the steel and slides sideways at the hinge side and does poorly at that when sticky with food. Clean and lube with a light coating of silicone lube, the door will close that last inch.

    How about self closing house doors? It’s getting cold again.

  3. Fridges don’t use much power at all. They are FAR from being one of the most energy hungry devices in the home. They use about the same power as a gaming computer idling (100w).

      1. I would hope not. The fridge should only be running when it needs to drop temperature, the rest of the time the insulating properties of the cabinet should maintain internal temperature.

        Which is why you aren’t supposed to leave the door open in the first place, or open it more than is necessary. That raises internal temp, and forces the refrigerator to wind back up to cool it down.

        Article in Forbes from 2015 says a gaming computer will consume over twice the energy as a fridge over the course of the year (many variables involved though, granted):

        https://www.forbes.com/sites/michaelkanellos/2015/09/07/the-big-surprise-in-home-energy-consumption-gaming-pcs/

  4. Loved this. My kids are not great at actually shutting the freezer AND they don’t pack it right, so no combination of springs or other bits are going to do the trick.

    That and the door shutting mechanism is rigged so that if a teen boy slams the top part of the fridge, the freezer part of the fridge pops open ever so slightly. Its just silly really – but I’ve lost many a good meal due to this little mishap.

    I recreated it with an actual esp8266. ;)

        1. Hah! Excellent suggestion. Further, I could send that to Amazon’s face reco and finally have a reason for the ‘in trouble’ spot on my Weasley clock…. Hmm I might have to do this in more places around the house.

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