I built this because our new home has a number of pinging ducts and I wanted to get to the bottom of it. So I decided to build something that could ‘hear’ through walls and display the number on a screen. In theory, this should allow me to pinpoint exactly where sounds might be located. I had a few components at my fingertips, one of them being the Sparkfun Microview which I might have even obtained way back when they had their Kickstarter campaign. I had built a pretty sweet…