I bought this EPSON XP-212 printer/scanner with the idea to power it off an inverter.

It works fine as a printer (including over wifi) but as a scanner I had to download driver from the EPSON web site, use teh USB connection, then Simple Scan didnt find it. I downloaded xsane instead, and that worked if I ran it as root

sudo xsane &

So I went to the Ubuntu forum https://help.ubuntu.com/community/Setti ... ermissions

and tried one of the solutions that was listed as dangerous:adding this to
/etc/udev/rules.d/40-scanner-permissions.rule

# usb scanner
SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", MODE:="0666"
SUBSYSTEM=="usb_device",MODE:="0666"

Well it works over USB. Is this ok as a solution or should I try to do something with groups and permissions? Also it still doesn't work over wifi as a scanner.

A little more detail on my blog http://billlions.blogspot.co.uk/2014/08 ... er-on.html

Have you tried the other (non-shotgun) solution suggested in the Ubuntu doc page you linkked to (i.e. editing /lib/udev/rules.d/40-libsane.rules)? Not sure if this would fix the wifi problem but seems easy enough to give it a try. You can get the required vendor and product id by connecting your (powered on) scanner to a usb port and then typing
into a terminal.

For me (using a different Epson scanner) this will produce: The second line shows the two ids.

Otherwise it seems you'd be OK with the permissions override approach on a single user system.

Yes, it didn't work. I was confused though that there did n't already seem to be a scanner or saned groups, I created them but I thought there must be another step so sane knows about that group?

I probably only have what the Germans call "dangerous half-knowledge" but here is what I think (just ignore if this is all old news to you - you may be way ahead of me on this...):

* In Unix more or less everything is treated as a file - including your scanner.
* You need read permission for the file that represents your scanner. The owner of that file will likely be 'root' but you can get read access by being/becomiing a member of the group associated with this file.

To find out which file represents you scanner plug it into a USB port and run. For me that yields one enrty that looks like this: So in this case I need to belong to group 'lp' to have read access to the scanner.

So if you add your user to whatever your system shows as the group with read access for the scanner's device file the whole thing *should* work?