For those who don't know our temperature, winter can easilly reach bellow -30C (-22F) and summer we sometimes hit around 30C (86F). This past few days have been quite cold reaching in the -26C with a wind chill effect of -35C so it was the best time to perform a cold powered-on test.
The setup was simple. A RaspberryPi running Raspbian with a DS18B20 temperature sensor, a Startech 4 port USB hub where an Arduino Uno is attached. Every 15s a script would record the temperature and every minute an other script would look (using lsusb) to see if the USB hub and Arduino were still alive. The setup looked like this:
The plastic container was scealed with tape, put in a 'ziplock' bag and left overnight on the rooftop of my car.
The power was provided by a small 75W APC DC-AC power inverter sitting in the car and connected to the car battery:
Well, according to the DS18B20 temperature sensor it got to about -22C last night and the resulting temperature graph looks like this:
Best of all no disconnection of the USB hub or Arduino were detected and the RaspberryPi did not reboot or lockup.