Pi 4 CW Keyer / QRQ CW Regenerator - using Python GPIO pin 7 square wave & an H11F1 FET Optoisolator

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



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Comment by Chuck aa0hw on October 28, 2022 at 9:01am


this setup uses CW REGENERATION to take a square wave from the Pi's GPiO PiN 7, created by a python script - send it to a FET OPTOisolator chip, that is 'keyed'(diode side) by a cw keyer's RIG KEYING JACK and a straight key...output of FET's GPiO python square wave then passes through the FET('n' side) & goes to the LiNE iNPUT of the pi's USB SOUND CARD ...then...INSIDE the pi software connection bay... TRIGGER MIDI MONO app analyzes the CW element timing and sends out a MiDi message \\ NOTE_ON//\\NOTE_OFF// that 'keys' the RECRI keyer-tone CPO... output of CPO goes to a FILTER then to an SDR MIXER so you can adjust the pitch of the CW according to your preference 

- the CW REGENERATION process only takes about 5 to 6 milliseconds to complete

- this whole CW KEYER setup operates at NEAR ZERO LATENCY

HARDWARE: pi4, h11f1 fet optoisolator, usb sound card with line input, couple of resistors & caps...

SOFTWARE: Trigger midi mono https://lsp-plug.in/?page=manuals&section=trigger_midi_mono RECRI KEYER's keyer-tone, lo-mixer, & filt modules https://github.com/recri/keyer python SQUARE WAVE on GPIO PIN 7 https://gist.github.com/bill314/92ca03d2892f146b967606a71e756c62

Comment by Chuck aa0hw on November 5, 2022 at 6:50am

Build a keyed Morse Code Practice Oscillator with raised cosine edges using a Raspberry Pi 4


uses an H11F1 FET optoisolator which gets KEYED on its diode side... on the 'N' side of this FET OPTO, a continuous sine wave generated by a Gstreamer Script, is outputted to the pi4 bcm2835 headhpone jack, which is the source of the CW AUDIO NOTE input for a PI4 CW REGENERATION software chain... the keyed FET OPTO allows the sine wave from the bcm2835's headphone jack output to pass through the FET OPTO to another pi sound card Line input, a usb sound card, the Behringer UCA222...the LINE INPUT of the UCA222 connects to the input of an AUDIO to MIDI app called TRIGGER MIDI MONO(TMM) https://lsp-plug.in/?page=manuals&section=trigger_midi_mono TMM analyzes the start/stop of each CW AUDIO element from the bcm2835 sine wave output(keyed by the FET opto) and outputs a MIDI NOTE(note 0/zero) and sends it to a midi CW KEYER's midi input port...the output of the CW KEYER is a new AUDIO CW Note with adjustable rise/fall/pitch/raised cosine/volume the output of the CW KEYER goes to a CW AUDIO BANDPASS FITER then to a CW LO-MIXER module where the CW PITCH setting of the MIXER tracks perfectly with the CW AUDIO BANDPass settings the CW keyer, filter and mixer are all modules from RECRI KEYER: https://github.com/recri/keyer


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