A holiday activity, build your own CW decoder that can handle up to 40 WPM including logic control to determine the CW code speed. There is a 567 tone decoder chip and some signal pre-processing, 8 ohm stereo audio goes in, next you print the decoded text on the serial output and on the LCD screen.
Version 2.4 has a status bar, most left number counts frames, then WPM guess followed by quality parameters.
This is version 2.3 that includes a quality of code filter.
This is version 2 that clearly had some bugs that were fixed
Note: I’m not sharing too much details yet because I’m still working on the software which is roughly 1000 lines in C/C++ Arduino style, still it compiles to 11k of code and less than 1 k of variables. The hardware resembles the design made by WB7FHC Budd but I’ve changed some stuff before it goes in the 567 tone decoder IC. The magazine Electron Dec 2018 jaargang 73 discusses a similar project.
Last update: 9-jan-2019