The NucleoTNC is a breadboard implementation of our commercial product, the Mobilinkd TNC3, designed to encourage experimentation and learning in amateur radio, electronics, digital signal processing and software engineering.
The TNC can be built with about $25 in parts. Build instructions, schematics in KiCAD format, and source code are available from our public GitHub repo.
Go here to see how to make your own TNC for $25: https://nbviewer.jupyter.org/github/mobilinkd/NucleoTNC/blob/master/Build/NucleoTNC.ipynb
If you make this project, we would love to see photos of your build on the Mobilinkd group: https://groups.io/g/mobilinkd
Update August, 2020: We have recently made available both a PCB and an enclosure for the NucleoTNC. There are just a few small part changes to make the project work better on a PCB. But you can take almost all of the parts from the breadboard and solder them onto a PCB and give your project a more permanent home.
Just released in early 2021 is experimental support for 9600 baud G3RUH/GFSK and M17 Project streaming and packet modes. This firmware release is meant for those wanting to contribute the development of the M17 protocol and need a baseband implementation to experiment with.