The Raspberry Pi Pico was the first Microcontroller build by the Raspberry Pi foundation, and you know what? You can use it as an SDR !
The idea is to use the ADC of the Pico to sample and forward the data via emulated TCP/IP to a regular PC where you can run your favorite SDR software
More information on this project can be found on github at this page:
https://github.com/luigifcruz/pico-stuff/tree/main/apps/piccolosdr