I grew frustrated with closed source ADS-B receivers a few years ago, and wanted to build a true low cost embedded ADS-B receiver from scratch for low power applications. I ended up developing a custom radio frontend that uses RP2040 PIO for Mode S preamble detection and demodulation, and also released the first open soruce implementation of UAT decoding on an RF MCU from TI (which works somewhat beyond the publicly stated specs for the chip). Today, ADSBee is a fully featured dual-band ADS-B receiver, with Mode S, ADSB, UAT ADSB, UAT TIS-B / FIS-B, a ton of configurable reporting protocols, WiFi / USB / Ethernet, and a web server. Beta testers have been using ADSBee to feed everything from online data aggregators to drone autopilot systems and tablets running Electronic Flight Bag apps like ForeFlight.

I'd love to hear what people think about the project, or answer any questions. I've been posting regular updates to the blog on my website, it's been a very fun journey taking an open source hardware project from an idea to a business that makes and ships real things: https://pantsforbirds.com/blog/