Ernie, here's the Auber manual for the 1503. Should tell you what you want to know. You can also go on Auber's website for tons of info.
www.auberins.comWhile you can certainly reinvent the wheel, and maybe save a few bucks, I can't recommend the folks at Auber enough. If you go to their website, you'll see they know their stuff - very well! They have perfected the technology for more than just electric smokers. These are scientific instruments, with very exact performance tolerances, that they have adapted to a specific need.
If I had it to do over again, I'd still go with Auber. It's a turn-key solution that is well-proven. Sometimes it's best to just go with an off-the-shelf solution because it a) saves time, and b) WORKS! I like the "works" part best! Simple to use, highly-accurate, and reliable from a solid company. What more could a Q chef want?? Just cover it in the rain, and you'll be fine.