Hi,

I'm just in the process of putting together a multi-node sensor array. There are five nodes each containing a PIC18F25K80 series Micro-controller. They are connected together with CAT5 and communicate with Can-bus.
Now my question is about powering each node. I was initially going to use separate wall warts but since all the nodes are fairly close together (<2 feet) that seemed like a waste, plus I would need a lot of plugs. So I was thinking of providing power over the CAT5 cable instead (like a diy POE).

I was thinking of using a 48vdc power supply as the source but I'm looking for some recommendations of how to handle the power at each node.
Is a DC to DC Step down converter the standard deal here, or is there something else I should be considering? Should it be Isolated? The current draw at each node is low < 100 ma.

Maybe something like this:
http://www.ti.com/lit/ds/symlink/ptma402050.pdf
or
http://www.adafruit.com/products/1066

 

The can bus itself is not an isolated bus, correct? I've never used one. But if the bus isn't isolated then any power isolation will be bypassed anyway, so it isn't needed.

Personally I'd pick a voltage closer to what the PIC's would run off of, put a local linear regulator (a low drop out no doubt) at each terminal and call it a day.