I regularly back-up my Raspberry Pi storage card because it’s so easy to damage the card with an improper shutdown or some such. I back up to a Mac, and you can read how I do it here. This wasn’t much of a chore in the early days when I was working with 4GB cards, but now I use 16GB Micro SDs and I know of folks who have much, much larger storage capacities thanks to never-cheaper cards. All this means the back-up takes a long time. So I wondered if I could create a gadget to tell me the task was done, allowing me to get on with other jobs in the meantime.