XPost: rec.radio.amateur.moderated

Ham radio ON7IR

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Morseduino build in 2017

Posted: 15 Dec 2021 03:52 AM PST https://on7ir.blogspot.com/2021/12/morseduino-build-in-2017.html


It has been a while since the last blog article here. The reason is simple,
I am currently not working on any project. Sometimes I read that people ask
for a good morse decoder. Four years ago I made the Morseduino from Budd Churchward WB7FHC and wrote about it on my Arduino blog in dutch language.
So here is a shortened version of that article. Today there is an updated hardware and software version of the Morseduino, see WB7FHC's website but
below is what I used in 2017.
But before you read further: The Morseduino decoder is good but the best decoder is between your ears!
The Morseduino has been made by a lot of people, sometimes with a modified sketch (the software). I used version 2.3 which still can be found at http://mypetarduino.com/MorseduinoSketch2.3.htm . It uses the Arduino's
analog ports A0 to A6 for driving the LCD display.
Referring to the circuit found at the Veron website (the Dutch hamradio association) below an overview of the changes I made.
- all parts are soldered on an experimental pcb
- I used an Arduino Pro Mini
- no power supply circuit. I use power from the USB port
- potmeter 2K2 is a 5K Ohm. I had no 2K2 available. I placed the
potentiometer at the back of the case because once set you don't have to
change it.
- the 220nF capacitors were replaced by two 100nF in parallel. Same reason,
had no 220nF in spare... however that's not true. I had one 220nF elco that
I used instead of the 330nF one at pin 2 of the LM567. This means that the 315Hz bandpass filter slightly increased to 385HZ, no big deal.
- the 10K potmeter is a linear one. The lock frequency is adjustable
between 550Hz and 2000Hz.
- no input for a morsekey is made so 47R resistor or 5V zener were omitted.
- between GND and pins D5 and D6 pushbuttons were provided (in the sketch
they are called switch1 and switch2). Only usable with software version 2
but not really needed. They are used to set speed and software QRN noise filter. I set them respectively to 30 and 4. These settings are saved in memory.
- between GND and Arduino Reset pin a pushbutton has been connected, just
in case the Arduino needs to be reset. Sometimes the speed of morse signs
is no longer synchronized resulting in only the letters E and T are being displayed. After a reset Morseduino adjusts nicely to the speed again.

- the LCD display is now connected this way :-
pin 1 - gnd
pin 2 - Vcc (5V)
pin 3 - gnd
pin 4 - Arduino pin A5
pin 5 - gnd
pin 6 - Arduino A4
pin 11 - Arduino A3
pin 12 - Arduino A2
pin 13 - Arduino A1
pin 14 - Arduino A0
pin 15 - via 22 ohm resistor to Vcc
pin 16 - gnd
- an advantage of the LCD display that I used is that there is no
potentiometer required for adjusting the contrast as best contrast was with
LCD pin 3 to GND. The LCD is connected to the experimental pcb on a 2x20
pins female connector because I had no 1x16 pins connector at that time available.
- with software version 2 one can put a loudspeaker between pin D9 and GND
and a morsekey between D8 and GND so that you can hear your morse signs. I
did not provide this.
- a plastic Velleman box 13x7x4.2mm is used. The frequency lock
potentiometer is placed at the right side. At the back there is the USB connector, a 3.5mm connector and potmeter R2.
Some pictures:-Morseduino in action during a CW contest
What is where
Ready to fit in the Velleman box
Backside
Frequency lock the right side. The scale is calibrated using an
audiogenerator

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