I purchased a Hobo from Onset 6 or 7 years ago that records inside and outside temp. I wanted to track the temp. in a converted chest freezer that I stored pesticides in. The chest freezer was heated by a 40 watt bulb on a simple thermostat switch and set at 40° F, I set the timer to take inside and outside temps each 1/2 hour through out the winter from Nov. to April. This was in an unheated garage and the set up worked well, the Hobo provided evidence that the thermostat controlled the light and that 40 watts was sufficient for the chest size I was using. This was a design check for a simple pesticide storage solution that was advocated by extension service employees but they couldn't provide any evidence that it was effective.

Since then I have deployed it to record ground temp. at 2 inches and at 4 ft. again using 15 min. intervals from mid April until early Nov.