Rx7man

It really depends on the application.. for some things humidity is completely irrelevant, and on others it is essential.

I was thinking of making a tobacco curing oven.. humidity would be critical on that application

I understand the theory behind them, and yes, they I can't deny they're good things to use.. I'll get some when I get my mouser or digikey order in.

I will have to look into optoisolators, but to start with I'll do most of my stuff with Zener diodes and/or resistor divider circuits.. I don't have a big enough toolbox of parts (yet) to play with them.... I do tear apart the odd piece of old equipment and pillage some IC's from them, then look up the datasheets and see what they're for.. haven't run into any optoisolators yet

I certainly can't contest thepower of the processor, but unless you're doing some serious number crunching I just think it could use more IO to make the most of it.  I will be getting one.. someday when this project starts to grow, and hopefully pay some dividends!

That sounds very good .. I currently have a Arduino shield based on a MCP2551 / MCP 2515, but I saw that some of these MCU's have it onboard.. so it would just be a matter of breaking it out if it did
 

That shield base looks good.. would those new IO's be 3.3 or 5V? I didnt see that listed there.

I was looking for a definition of "Gobus" on google but all I found were references to city transit, is that available somewhere as well?

Cheers and thanks!