Emerson's handheld scanner is built on top of a Raspberry Pi and uses various sensors to scan for RF signals and thermal bodies. It even has a built-in speaker to play the radio signals out loud.
This was Emerson’s first foray into Raspberry Pi territory and the results were absolutely worth it. The test version of the Raspberry Pi scanner was housed inside a Tupperware container which he affectionately dubbed the world's first redneck tricorder and, according to Emerson, was able to accurately detect a Klingon trailer park.
He ordered more parts for the final build which ended up inside a clear waterproof shell. It has a display operated by the Raspberry Pi which puts out visual data for both the RF scanner and thermal camera. He also included a battery pack so the unit is completely portable.
In the video, he experimented with an environmental sensor which reads both temperature and humidity but didn't have much luck, but this was likely due to a bad sensor module. There are plans in the works to update the scanner with more sensors and functions. In the meantime, check out his work on the official saveitforparts website. You may enjoy his steam-powered RC goose project.