Digispark

Arduino IDE

Install the arduino IDE and the libusb-compat package.

pacman -S arduino arduino-avr-core
pacman -S libusb-compat

Add the driver with the following URL in Arduino (File -> Preferences -> Additional Board Manager URLs).

https://raw.githubusercontent.com/digistump/arduino-boards-index/master/package_digistump_index.json

Add udev rules

/etc/udev/rules.d/49-micronucleus.rules

# UDEV Rules for Micronucleus boards including the Digispark.
#
SUBSYSTEMS=="usb", ATTRS{idVendor}=="16d0", ATTRS{idProduct}=="0753", MODE:="0666"
KERNEL=="ttyACM*", ATTRS{idVendor}=="16d0", ATTRS{idProduct}=="0753", MODE:="0666", ENV{ID_MM_DEVICE_IGNORE}="1"
#
# If you share your linux system with other users, or just don't like the
# idea of write permission for everybody, you can replace MODE:="0666" with
# OWNER:="yourusername" to create the device owned by you, or with
# GROUP:="somegroupname" and mange access using standard unix groups.

Troubleshooting page

See here with this general tutorial.