Every machine has its own way of communicating with its operator. Some send status emails, some illuminate, but most of them vibrate and make noise. If it hums happily, that’s usually a good sign, but ...

Arduino Nano firmware that turns an nRF24L01(+/+PA+LNA) module into a 2.4 GHz spectrum scanner and streams the data over USB serial as plain CSV. A host program (your visualizer) reads /dev/ttyUSB0 ...