Growing The World’s Largest Snowflake

Plenty of areas around the world don’t get any snowfall, so if you live in one of these places you’ll need to travel to experience the true joy of winter. If you’re not willing to travel, though, you could make some similar ice crystals yourself instead. While this build from [Brian] aka [AlphaPhoenix] doesn’t generate a flurry of small ice crystals, it does generate a single enormous one in a very specific way.

The ice that [Brian] is growing is created in a pressure chamber that has been set up specifically for this hexagonal crystal. Unlike common ice that is made up of randomly arranged and varying crystals frozen together, this enormous block of ice is actually one single crystal. When the air is pumped out of the pressure chamber, the only thing left in the vessel is the seed crystal and water vapor. A custom peltier cooler inside with an attached heat sink serves a double purpose, both to keep the ice crystal cold (and growing) and to heat up a small pool of water at the bottom of the vessel to increase the amount of water vapor in the chamber, which will eventually be deposited onto the crystal in the specific hexagonal shape.

The build is interesting to watch, and since the ice crystal growth had to be filmed inside of a freezer there’s perhaps a second hack here which involved getting the camera gear set up in that unusual environment. Either way, the giant snowball of an ice crystal eventually came out of the freezer after many tries, and isn’t the first time we’ve seen interesting applications for custom peltier coolers, either.

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This Freezer Failure Alarm Keeps Your Spoils Unspoiled

Deep freezers are a great thing to have, especially when the world gets apocalyptic. Of course, freezers are only good when they’re operating properly. And since they’re usually chillin’ out of sight and full of precious goods, keeping an eye on them is important.

When [Adam] started looking at commercial freezer alarms, he found that most of them are a joke. A bunch are battery-powered, and many people complain that they’re too quiet to do any good. And you’d best hope that the freezer fails while you’re home and awake, because they just stop sounding the alarm after a certain amount of time, probably to save battery.

If you want something done right, you have to do it yourself. [Adam]’s homemade freezer failure alarm is a cheap and open solution that ticks all the boxen. It runs on mains power and uses a 100dB piezo buzzer for ear-splitting effectiveness to alert [Adam] whenever the freezer is at 32°F/0°C or above.

If the Arduino loses sight of the DHT22 temperature sensor inside the freezer, then the alarm sounds continuously. And if [Adam] is ever curious about the temperature in the freezer, it’s right there on the 7-segment. Pretty elegant if you ask us. We’ve got the demo video thawing after the break, but you might wanna turn your sound down a lot.

You could assume that the freezer is freezing as long as it has power. In that case, just use a 555.

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Build Your Own Freezer With Thermoelectric Coolers

Freezers are highly useful devices. You can preserve food, stop a dead animal from stinking out your apartment, and keep your vodka at the optimal drinking temperature. Of course, most of us bought ours from the local whitegoods store, but [Tech Ingredients] set out to build his own (YouTube, embedded below).

Unlike your freezer at home, this build doesn’t use the typical heat pump and refrigeration cycle with a compressor and expansion valve and so on. Instead, this freezer uses thermoelectric devices to pump heat, in combination with a glycol cooling circuit and fan-cooled radiators.

It’s not the most efficient or practical way to build a freezer, but it is functional and the device demonstrably works, making ice cubes over the course of a few hours. Performance can be further improved by moving the radiator assembly outdoors to make the most of the low ambient temperatures.

[Tech Ingredients] has further plans to experiment with a dessicant-based refrigeration system, and reports that initial results are promising. We’re eager to see how that goes; we’re fans of any rig that can cool a beer down in no time flat. Video after the break.

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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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Fight Frost With An Internet Of Things Fridge Alarm

It has been incredibly humid around these parts over the last week, and there seems to be something about these dog days that makes you leave the fridge or freezer door open by mistake. [pnjensen] found this happening all too often to the family chill chest, with the predictable accretion of frost on the coils as the water vapor condensed out of the entrained humid air and froze. The WiFi-enabled fridge alarm he built to fight this is a pretty neat hack with lots of potential for expansion.

Based on a Sparkfun ESP8266 Thing and home-brew door sensors built from copper tape, the alarm is rigged to sound after 120 seconds of the door being open. From the description it seems like the on-board buzzer provides a periodic reminder pip while the door is open before going into constant alarm and sending an SMS message or email; that’s a nice touch, and having the local alarm in addition to the text or email is good practice. As a bonus, [pjensen] also gets a log of each opening and closing of the fridge and freezer. As for expansion, the I2C header is just waiting for more sensors to be added, and the built-in LiPo charger would provide redundancy in a power failure.

If frost buildup is less a problem for you than midnight snack runs causing another kind of buildup, you might want to check out this willpower-enhancing IoT fridge alarm.

Over Engineered Kegerator Is Glorious

keger

When [Joey] decided to build a kegerator, he didn’t skimp. No commercial unit or simple kit would do. [Joey] wanted complete temperature monitoring, with a tap on the kegerator itself and a cooled tap remotely mounted at his bar. He started with a box freezer, which was a bit short for his purposes. Not a problem, as [Joey] cut an extended collar for the freezer from HDPE on his shopbot. The new collar gives mounting points for the beer lines, gas lines, as well as all the electronics.

Temperature control is handled by a commercial controller, however temperature monitoring is another thing altogether. An Arduino sits in a custom aluminum case on the outside of the kegerator. The Arduino reports temperature, beer type and also controls the cooling system for the beer lines. The cooling system alone is incredible. [Joey] designed everything in CAD and cut the parts out on his shopbot. Two fans sit in an aluminum air box. One fan is used to push cold air out from the freezer around the beer line. A second fan pulls air back in, keeping the kegerator/line/tap air system a (relatively) closed loop. The entire line set is insulated with 2″ fiberglass flex duct.

Temperature data and trend graphs can be monitored on the web, and [Joey] is using a Raspberry Pi to create a wall mounted status screen for his bar room. We love this build! [Joey] we’d buy you a beer, but it seems like you’ve got that covered already!

Freezing Android To Crack The Encryption

frozen-phone-encryption-hacking

Build a better lock and someone will make a tool to open it without the key. Or in this case they’ve made a tool to discover the key using a trip to through the deep freeze. The Forensic Recovery of Scrambled Telephones — or FROST — uses cold temperatures and a custom recovery image to crack Android encryption keys.

Cold boot hacks go way back. They leverage use of low temperatures to slow down the RAM in a device. In this case, the target phone must already be powered on. Booting a phone that uses the encryption offered by Android 4.0 and newer requires the owner’s pass code to decrypt the user partition. But it then remains usable until the next power cycle. By freezing the phone, then very quickly disconnecting and reconnecting the battery, researchers were able to flash their own recovery image without having the encryption key cleared from RAM. As you can see above, that recovery package can snoop for the key in several different ways.

[Thanks Rob]