I guess i don't fully understand. how are you going to use the camera if its in a explosion proof box? Anyway we have been building liquid baths for class1 div1 labs and have been using I beleive an Appleton enclosure. I think our price is around $1200. I'm not sure if its what you had in mind...
Seriously though, if you don't want to use the programmable relay like Itsmoked suggested, you could use a Micrologix 1000 or a GE Versamx Micro processor for almost as cheap. But then you would have to find software. I think Ge has a trial of Proficy Machine Edition that you have to reinstall...
itsmoked....its been along time since i've heard people talk about voltage dividers and transistors. Lets just can this PLC stuff and do this project with PIC chips and ohms law...... Good Times.
