The experiment is over
20 hours with periodic bullying - normal flight.

Task

Since Virturilka is used in motor transport and in some street devices, it was necessary to check how it works at negative temperatures, and then winter is already on the nose. In theory, if there is no condensation, then it should hold out for a while with a minus. But to what subzero temperature the working capacity will remain and what will happen to the condensate is unknown, it is necessary to check. Moreover, it should be checked in bare form - the piece of iron should be placed in a cold room as it is, without any closed box, because the percent heats up (and the Wi-Fi chip too), as a result, the box will be warmed from the inside by Virturilka itself.
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Where to get a minus temperature in the living conditions (outside the window is still positive plus)? Of course, in the fridge :-) More precisely, in the freezer. Judging by the asterisks painted on the refrigerator door and the description on Wikipedia, this signature "* (***)" indicates the potential possibility of the freezer to arrange a frost of 18 degrees or more.

At the same time I will get an answer to the question that has long been sitting in my head - whether wi-fi will work from a closed metal refrigerator.

What happened

Virtuillare was placed in an open box, more precisely, from the box there is only the base and walls. This is to ensure that the piece of iron on the metal bottom of the freezer does not lie. Although the bottom and painted, but still somehow I do not want to just put.

Our ordinary camera is connected to Virturilka. Video from the camera is sent to the YATV server, from where it can be viewed with their own player, embedded on a specially made page.

Communication - via WiFi, through our module based on the Marvell W8686.

Power is brought from the outside, from the power supply to 5V.

Also, a well-known thermometer DS18B20 is connected to the Virturile, which is polled once a second and the received information about the temperature is sent to the server. The client script on the web page every second loads the information from the thermometer and displays it in the browser. It seems simple.

For feedback, two references are made, clicking on which lights or extinguishes the LED onboard the virtual video.

The focus of the camera is fixed, the focal length is greater than the distance at which the camera is from the piece of iron, so the video is not entirely in focus, but the main components seem to be visible.



You can see whether Virtualvilka is still alive in the fridge, here http://video.virt2real.ru/show/subzero/

Preliminary results

I put the piece of iron in the refrigerator at about one in the morning. At first, the temperature kept around -6 degrees, I began to think that the percent and the Wi-Fi are so hot that they heat up the entire freezer compartment. But soon the temperature crept briskly down - the compressor turned on. I forgot that it does not always work. The minimum recorded temperature is minus 19.64 degrees. After the compressor is turned off, the temperature rises to about 11-12 degrees below zero. Then, after some time, it goes down again and so on in the cycle.



Wi-Fi works fine. Pah-pah-pah, the signal level inside the refrigerator is not worse than outside.

So, now (half past five in the morning) the piece of iron is already in the refrigerator for more than four hours, the flight is normal. Testing will be until Sunday evening, you never know, maybe the piece of iron, or the camera, or something else may die. The main thing that the refrigerator compressor is not dead, and then the wife will kill for such experiments.

Of course, this is not so outstanding an experiment, rather than in the case of overclocking the Arduino under liquid nitrogen (BarsMonstruh Respect), but for practical purposes it will completely go away.

UPD> If someone offers a complication of the experiment, well in the comments. If someone wants to offer something, but can not write on Habr - write comments here .

forum.virt2real
wiki.virt2real

UPD> Here they suggest that Malina has already been frozen. Thanks for the reference, have not seen before. habrahabr.ru/post/178647