So I've entered the relatively new digital modes (for me anyway) of DMR & YSF. This requires either a digital repeater or personal hotspot to access. The popular way to do this is with a software suite called MMDVM and currently there's two Raspberry Pi images available that take care of having to build everything yourself. The first is PiStar and the other is by KB5RAB
I'm using the Pi-star image as it's headless (meaning it doesn't require a keyboard & monitor to run)and uses a webui to configure and uses a read-only file system once everything is loaded, whereas the KB5RAB is a full Raspbian desktop. As you can see from the pictures I'm using a Raspberry Pi2 and the ZUMSpot Pi and a dual colour OLED.
When portable I have 10000 (mAh) 5v power pack that is about the same size as the case I'm using for the Pi2, so a few rubber bands double looped holds it all together rather nicely! The ZUMSpot Pi hat is the perfect size for fitting the OLED screen inside the case using some double sided foam tape stuck to the HDMI socket and the very top edge of OLED is resting on the CPU heat sink. Initially I was going to attach the I2C ribbon cable to the bottom of the Raspberry Pi, but if I ever want to swap the ZUMSpot out I'd be without the OLED so instead I attached it to the ZUMSpot hat.
Finally links to items…
Pi-Star by Andy Taylor
ZUMSpot Pi by Bruce Given