this video is a follow video - from the 2 previous videos here on this topic:
in this video the same setup as in the 2nd video above is used and tested to see if can perform QRQ CW KEYING - from 60 wpm to 120 wpm FLdigi is keying an H11F1 fet that 'key's a pi4 python continuous square wave from GPIO pin 7 ...the python GPIO pin 7 square wave input to H11F1 FET output - connects to the pi4's usb sound card line input when the FET is keyed by FLdigi's serial port RTS pin(diode side of the FET)....
a small pi touch screen allows adjusting of all CW Parameters inside the pi,
TRIGGER MIDI MONO and RECRI KEYER modules perform the CW REGENERATION and outputs a NEW CW NOTE(s) with adjustable raised cosine edges , adjustable pitch and volume, rise/fall time etc...
simple python code from : https://gist.github.com/boseji/7296415