RE: Heat .....
Try putting it so that it is looking down a trail rather than across it, I have the stealth cam, had the same trouble you had at first. Find a good funnel in the wood close to your plot and set up their. I have a ditch running though a bottom parralel to my plot and I cut brush all along it making a natural fence except in one spot where I opened a trail crossing the creek and straight up to my plot, took about 2 weeks for the deer to get used to it but now they use it every evening. Keep in mind the wind and stand placement if you try this good luck. Gabe