Digital general coverage radio receiver.It is written for a standard Arduino UNO but could probably run on other Arduinos too. Should you fancy to roll one yourself here is the code for the project (AS IS, no helpsies!). all the parts are just connected with wires: The schematic for the project is really straight forward. Since the analyzer was meant to identify channel occupancy I added a feature that would identify the most occupied channel and put a circle around this peak value as well as it’s frequency. These are the numbers that are displayed as a graph on the display: I therefore used a simple histogram method where I quickly scanned through all channels and counted up a number for each channel if it was occupied. The NRF27L01 does not really have the capability to measure the signal strength of a particular channel but just if the channel is occupied or not. I wanted something that only looked at the radio signals and did not try to interpret SSID’s and other WiFi related stuff, I just wanted to know if there was activity on the channel or not. The NRF24L01 is not really meant to interact with WiFi signals but its frequency range does cover the 2.4GHz WiFi channels. In frustration I made this quick and dirty spectrum analyzer using a NRF24L01 module, an Arduino and a small OLED display: Sometimes you could get a brief connection but the connection would carry no bandwidth or quickly disappear. Several wireless routers and configurations was tried but nothing seemed to work. For a while the 2.4Ghz WiFi in the lab did not work at all.

Wifi frequency analyzer