isolation requirements

Im planning to interface the A2D channels (and a couple dio channels) on my board with sensors which are in a garage/shop environment, and the sensors are located in a remote box connected via a cable. Im curious how sensitive the board is, and if i should use some form of isolation for the a2d and dio channels? Or is the board considered rugged enough for this kind of useage? Thanks

Well, is there a chance that external voltages will be applied to the cable wires? Are the sensors powered from the board or are they externally powered? If they are externally powered (12V for example) there is a chance that due to miswiring or shorts or whatnot you could see 12V on your board which could destroy it.

More details?

http://www.ruggedcircuits.com

How good is the arduino at picking up signals over long distances anyway? It would be better to have an external A2D connected via i2c? At least you won't have EM inductance to contend with then. You might get more channels too.. Also, perhaps some sort of noise cancelation on the io circuits?

eg:

Arduino -> Base + Collector of Transistor -> Emittor to signal? Not sure, and you'd need 2 perhaps for each direction?

no external power, basically just going to be measuring the positiion of a potentiometer. and not concerened about absolute potion, just taking a start and end position for a delta.

Just hooking up a passive device like a potentiometer should be fine. I don’t know where the digital I/O are going (is that what you meant by “dio”???)

But over a long cable, your analog signal could pick up quite a bit of noise. As long as you don’t expect a super-precise signal on the A/D input you should be OK.