New Year Testing Wiren Board

When we released the Wiren Board - a compact industrial computer with Wi-Fi, GPRS, GPS and NFC - many asked us if we tested it at extreme temperatures. Usually we answered that all the components of the Wiren Board were selected for the industrial range, and you need to test the finished devices in the case.
But on New Year’s, real miracles happen - and today we publish a report on testing the Wiren Board with ice and flame. And the real Snow Maiden will help us with this!

They say: on New Year's Eve whatever you wish ...

We will conduct tests on the performance of Wiren Board as is in the widest temperature range. Although all components are selected in an industrial design, problems of a purely circuit design are possible. For example, the capacity of electrolytic capacitors drops more than twice when cooled to -50 ° C, which means that ripples in the supply circuits increase, and unstable operation is possible.

How do we do this?

Preliminary experiments showed that if you just put the board in the refrigerator, it will cool too quickly and unevenly. For a gradual cooling, we placed the Wiren Board in a cardboard box. The board was mounted on racks and was blown sideways by a fan, which was connected to the low-voltage load control terminals. A fan is needed to quickly equalize the temperature inside the box. External GPS and GSM antennas were also connected to the Wiren Board.

The processor in the Wiren Board has a special temperature sensor that allows you to measure the temperature of the processor chip. To measure the external temperature, we connected to the Wiren Board the favorite DS18B20 external digital thermometer through the 1-wire interface ( an example of connection in our wiki).



A Python script running on the board collected data (uptime, timestamp, temperatures, as well as a list of wifi networks, usb status, GPS coordinates, etc.), saved them to the device’s internal memory, and sent them via GPRS to the Internet. To receive data, we used the Loggly service:

And heavy unbearable heat

To heat, we gradually forced hot air into the hole in the box using a regular hair dryer. The temperature inside the box was balanced by a fan.


At the 37th minute, at an ambient temperature of 75 degrees (crystal 87 ° C), the GPS signal was lost. GPS re-captured satellites briefly after 3 minutes at 95 degrees. At the 42nd minute at 114 degrees (crystal 113 ° С) the GSM / GPRS connection was lost. After another couple of minutes at 116 degrees, errors started when working with a USB hub. At a temperature of about 120 degrees, the core finally fell into kernel panic.
The Wiren Board survived overheating without loss, all systems continued to work without any problems after cooling.

Not from the cold, the mountain ash trembles

It was not possible to catch the harsh Russian winter in Moscow on New Year's Eve, so we had to freeze the Wiren Board in the refrigerator. No, of course, not in an ordinary refrigerator, but in a low-temperature freezer at the MIPT biological laboratory, which can cool to -80 ° C.




Measurements in the refrigerator began when the temperature of the board managed to drop to 0 ° C. On the 19th minute at -50 ° C, the board stopped showing signs of life outside. After the reboot, the board, which had cooled to -59 degrees by this time, worked for several more minutes until it turned off completely. By thawing, Wiren Board is working again.

Summary

No matter how the Snow Maiden tried, she couldn’t freeze the Wiren Board - our computer was able to withstand the temperature drop to minus 50! He coped well with heating - the first failure (loss of satellites) occurred only at 75 ° C, and everything else continued to work up to 114 ° C.

New Year is knocking on the door! Open to him soon

In a few days, the New Year will come, and we, the company “Contactless devices”, have a whole bag of thanks and congratulations.

First of all, we say many thanks to the beautiful model Anastasia Azorkina and the photographer Alexander Lotsmanov , who turned our report into a little fairy tale.
We also thank the MIPT laboratory “Nanoconstruction of membrane-protein complexes to control cell physiology” for the provided freezer.

Finally, we thank you - our readers, Wiren Board users, all those who have commented and advised us. We walked alongside you all of 2013, listened to you, and tried very hard. It is you who help develop the Wiren Board, and we hope that our friendship will continue in the new year. We wish you to celebrate the New Year brightly and warmly, and in 2014 you will have good luck and new achievements!

And now a gift: until January 15 we make a 10% discount in our store - just enter the code WB2014NY when making the order.