Arduinos are a godsend for the DIY/Tinkerer community, but there’s all sorts of stuff they just can’t do out of the box. Sure, you can add tons of functionality via strap-on boards called “shields”..

[Leigh] is a HAM operator (you may know him as wa5znu). He is familiar with a signal visualization tool called a waterfall which plots signal strength and frequency over time. He wanted to build his ...