The problem seems to be that the device permissions are not being correctly set by udev when the board is plugged into the pc's usb connector.
If I run the Arduino IDE as root, it lets me use the ISP R3 usb programmer board. Not convenient for sketchbook management!
I can temporarily fix this problem by opening terminal, and typing
lsusb
to bring up a list of attached usb devices, then type
sudo chmod 666 /dev/bus/usb/006/005
(or whatever the bus/device number happens to be at the time), which lets me as an ordinary user write to the device from the IDE. So for now, I keep using this temporary fix.
Meanwhile, I have tried following the instructions at https://andreasrohner.at/posts/Electronics/How-to-fix-device-permissions-for-the-USBasp-programmer/ , in order to make a udev rule that should fix this, but no success yet.
I have created a new file called /etc/udev/rules.d/99-USB_ISP_R3.rules , which reads like this:
# UDEV rule for Arduino ISP R3 programmer board,
# to prevent having to run Arduino IDE as root to get it to program.
# Copy this file to /etc/udev/rules.d so
SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", SYSFS{idVendor}=="1781", SYSFS{idProduct}=="0C9f", MODE="0666"
and executed
gpasswd -a <username> uucp
but to no avail; I still have to use the temporary fix.
Please can anyone shine some light on this problem? Is there a patch for this anywhere?
Thanks, Matt.