In Harry Potter, there was a magical item called a Weasley Clock which showed where everyone in the family was at  particular time. Tom from Australia wrote in, wanting to design one but not sure how to get started. He’s new to embedded but is a software developer. I was amused by the idea of such a clock and procrastinating about another project so I put together a response. Happily, Tom says you can read his mail so here it is.