Ubufatanye
UBUHANZI
UBWIZA N'UBUZIMA
UBUKORIKORI
UMUCO N'AMATEKA
IMYIDAGADURO
IBIDUKIKIJE
IBIRIBWA N'IBINYOBWA
UBWUBATSI BUSUBIRA INYUMA
UBUMENYI
SIPORO
IKORANABUHANGA
IBYAMBARWA
Pocket Morse Code Learning Board - v.2
Admiral OOM

Yaremwe na

Admiral OOM

10. Ugushyingo 2026NO
5
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Pocket Morse Code Learning Board - v.2

The complete pocket Morse decoder, 88 x 62 mm: every letter, the figures 0-9, the thirteen punctuation signs of the international code and the accented E, each with its own LED on Dave Nathanson's decoding chart. Press the key short for a dot and long for a dash, and the LED of the character you have reached lights; pause, and it blinks. It runs on one CR2032 coin cell and sleeps between uses. The board was drawn with Youblob's Draw PCB, and its checks pass, but it has not been built yet.
Hejuru
About 1 day, plus board delivery

Amabwiriza

1

LED current and keying speed

Gupakira ikaye ya Jupyter…
2

The letters-only board, before it

The same design with 27 LEDs. This one adds the figures and the signs, 59 LEDs in all.
3

Read the chart

Dave Nathanson's (KG6ZJO) complete chart adds the figures to his letters: "A-Z and Numbers (I left off the punctuation & symbols for simplicity)". This board adds them back from ITU-R M.1677-1 on new branches: . , : ? ' - / ( ) " = + @ and the accented E. Eight unlabelled LEDs are waypoints on the way to a figure or sign.
4

The schematic

ATmega328P on its internal 8 MHz clock, straight from the coin cell; 59 LEDs charlieplexed on nine lines (PC0-PC5, PD0, PD1, PD3) through 300 Ω resistors; the key on INT0; a 2x3 ISP footprint.

Ikireba KiCanvas kirapakirwa...

Ikireba cy'Umwuga cy'Igishushanyo cya PCB

5

The board

Two layers, 88 x 62 mm. The chart, LEDs and key on the front; the chip, resistors, capacitors and cell holder on the back.

Ikireba KiCanvas kirapakirwa...

Ikireba cy'Umwuga cy'Igishushanyo cya PCB

6

Order the board

Open the board in KiCad and plot Gerber and drill files (File > Fabrication Outputs). Order a two-layer board, 1.6 mm thick, from any board maker that takes Gerbers.

Ibikoresho by'iyi ntambwe:

Ikibaho cy'umuzunguruko cyacapweIkibaho cy'umuzunguruko cyacapwe1 igice

Ibikoresho bikenewe:

Mudasobwa Ifite Arduino IDEMudasobwa Ifite Arduino IDE
7

Solder the parts

Back first: paste and reflow U1, R1-R10, C1-C3 and the cell holder BT1 with hot air. Then the front: the 59 red LEDs D1-D59 with pad 1 (cathode) as the board's assembly drawing shows, and the key SW1, a two-pad 6 x 6 mm switch to match its footprint. J1 is optional. Clean off the flux, then test each LED's direction with the meter's diode test.

Ibikoresho by'iyi ntambwe:

Mikorokontorolewa ATmega328PMikorokontorolewa ATmega328P1 igice
LED ya shipuLED ya shipu59 ibice
Rezisitansi ya shipuRezisitansi ya shipu10 ibice
Kondenseri ya seramike ya shipuKondenseri ya seramike ya shipu3 ibice
Buto ikandwaButo ikandwa1 igice
Igifata bateriIgifata bateri1 igice
Pasita yo gukomatanya (idafite plombi)Pasita yo gukomatanya (idafite plombi)1 igice
Urusinga rw'isudireUrusinga rw'isudire1 igice

Ibikoresho bikenewe:

Isitasiyo yo gusana n'umwuka ushyushyeIsitasiyo yo gusana n'umwuka ushyushye
Icyuma cyo gusudiraIcyuma cyo gusudira
Utwuma two gufata dufite impera zityayeUtwuma two gufata dufite impera zityaye
Umuti wo gusudiraUmuti wo gusudira
Indorerwamo YaguraIndorerwamo Yagura
Igipimo cy'amashanyarazi kinyuranyeIgipimo cy'amashanyarazi kinyuranye
Alukoli ya isopropili 99 %Alukoli ya isopropili 99 %
8

The firmware

pocket_morse_decoder_complete.ino: every timing is a named constant at the top of the sketch. Board in the Arduino IDE: Arduino Pro or Pro Mini, ATmega328P (3.3V, 8 MHz).
pocket_morse_decoder_complete.inoarduino
/*
  Pocket Morse decoder - firmware for ATmega328P-AU, internal 8 MHz, CR2032 (3 V)
  Board: Arduino Pro or Pro Mini, ATmega328P (3.3V, 8 MHz)  (fqbn arduino:avr:pro:cpu=8MHzatmega328)
  Fuses for the internal 8 MHz RC oscillator (set once with an ISP programmer):
    lfuse 0xE2, hfuse 0xD9, efuse 0xFF (brown-out detector off to save the coin cell)
  Upload with "Upload Using Programmer" over the 2x3 ISP header.

  59 LEDs are charlieplexed on 9 pins (each pin through its own 300 ohm resistor).
  Only one LED is ever lit.  Button on INT0 (D2) to GND, internal pull-up.
*/
#include <avr/sleep.h>
#include <avr/power.h>
#include <avr/pgmspace.h>

// ---------------- timings (milliseconds) ----------------
const unsigned long DASH_THRESHOLD_MS = 250;    // press shorter = dot, longer (or equal) = dash
const unsigned long CHAR_GAP_MS       = 700;    // no press for this long ends the character
const unsigned long IDLE_SLEEP_MS     = 30000;  // no press for this long -> all off, power-down sleep
const unsigned long BLINK_ON_MS       = 150;    // result blink: LED on time
const unsigned long BLINK_OFF_MS      = 150;    // result blink: LED off time
const uint8_t       BLINK_COUNT       = 3;      // number of result blinks
const unsigned long DEBOUNCE_MS       = 20;     // button debounce time

// ---------------- hardware ----------------
const uint8_t BUTTON_PIN = 2;                   // PD2 / INT0
// charlieplex lines L1..L9 -> PC0..PC5, PD0, PD1, PD3
const uint8_t LINE_PIN[9] = {A0, A1, A2, A3, A4, A5, 0, 1, 3};
const uint8_t MAX_CODE_LEN = 7;

struct Node { uint8_t len; uint8_t bits; uint8_t anode; uint8_t cathode; };
// bits: symbol j of the code is bit j (1 = dash). Index 0 is Start.
const Node NODES[] PROGMEM = {
  {0, 0x00, 0, 8},  // D1 S Start
  {1, 0x01, 3, 8},  // D2 - T
  {1, 0x00, 8, 0},  // D3 . E
  {2, 0x03, 3, 6},  // D4 -- M
  {2, 0x01, 6, 5},  // D5 -. N
  {2, 0x02, 0, 3},  // D6 .- A
  {2, 0x00, 8, 1},  // D7 .. I
  {3, 0x07, 3, 7},  // D8 --- O
  {3, 0x03, 6, 7},  // D9 --. G
  {3, 0x05, 5, 6},  // D10 -.- K
  {3, 0x01, 5, 2},  // D11 -.. D
  {3, 0x06, 4, 1},  // D12 .-- W
  {3, 0x02, 1, 7},  // D13 .-. R
  {3, 0x04, 1, 3},  // D14 ..- U
  {3, 0x00, 8, 3},  // D15 ... S
  {4, 0x0F, 3, 5},  // D16 ---- _
  {4, 0x07, 5, 7},  // D17 ---. _
  {4, 0x0B, 7, 6},  // D18 --.- Q
  {4, 0x03, 7, 8},  // D19 --.. Z
  {4, 0x0D, 8, 2},  // D20 -.-- Y
  {4, 0x05, 6, 2},  // D21 -.-. C
  {4, 0x09, 6, 0},  // D22 -..- X
  {4, 0x01, 2, 5},  // D23 -... B
  {4, 0x0E, 0, 1},  // D24 .--- J
  {4, 0x06, 2, 4},  // D25 .--. P
  {4, 0x0A, 1, 2},  // D26 .-.- _
  {4, 0x02, 7, 1},  // D27 .-.. L
  {4, 0x0C, 7, 2},  // D28 ..-- _
  {4, 0x04, 2, 1},  // D29 ..-. F
  {4, 0x08, 3, 4},  // D30 ...- V
  {4, 0x00, 8, 4},  // D31 .... H
  {5, 0x1F, 5, 3},  // D32 ----- 0
  {5, 0x0F, 7, 5},  // D33 ----. 9
  {5, 0x07, 8, 7},  // D34 ---.. 8
  {5, 0x13, 6, 8},  // D35 --..- _
  {5, 0x03, 8, 6},  // D36 --... 7
  {5, 0x0D, 2, 8},  // D37 -.--. (
  {5, 0x09, 0, 6},  // D38 -..-. /
  {5, 0x11, 0, 2},  // D39 -...- =
  {5, 0x01, 5, 0},  // D40 -.... 6
  {5, 0x1E, 1, 5},  // D41 .---- 1
  {5, 0x16, 0, 4},  // D42 .--.- _
  {5, 0x0A, 3, 2},  // D43 .-.-. +
  {5, 0x12, 2, 7},  // D44 .-..- _
  {5, 0x1C, 4, 0},  // D45 ..--- 2
  {5, 0x0C, 7, 4},  // D46 ..--. _
  {5, 0x04, 3, 1},  // D47 ..-.. É
  {5, 0x18, 1, 4},  // D48 ...-- 3
  {5, 0x10, 4, 3},  // D49 ....- 4
  {5, 0x00, 4, 8},  // D50 ..... 5
  {6, 0x07, 8, 5},  // D51 ---... :
  {6, 0x33, 5, 8},  // D52 --..-- ,
  {6, 0x2D, 2, 6},  // D53 -.--.- )
  {6, 0x21, 0, 5},  // D54 -....- -
  {6, 0x1E, 5, 1},  // D55 .----. '
  {6, 0x16, 2, 0},  // D56 .--.-. @
  {6, 0x2A, 3, 0},  // D57 .-.-.- .
  {6, 0x12, 4, 2},  // D58 .-..-. "
  {6, 0x0C, 4, 7},  // D59 ..--.. ?
};
const uint8_t NODE_COUNT = sizeof(NODES) / sizeof(NODES[0]);
const uint8_t START_NODE = 0;
const int8_t  NO_NODE = -1;

volatile bool wokeUp = false;

void allOff() {
  for (uint8_t i = 0; i < 9; i++) {
    pinMode(LINE_PIN[i], INPUT);
    digitalWrite(LINE_PIN[i], LOW);
  }
}

void lightNode(int8_t idx) {
  allOff();
  if (idx < 0 || idx >= NODE_COUNT) return;
  uint8_t a = pgm_read_byte(&NODES[idx].anode);
  uint8_t k = pgm_read_byte(&NODES[idx].cathode);
  digitalWrite(LINE_PIN[k], LOW);
  pinMode(LINE_PIN[k], OUTPUT);
  digitalWrite(LINE_PIN[a], HIGH);
  pinMode(LINE_PIN[a], OUTPUT);
}

int8_t findNode(uint8_t len, uint8_t bits) {
  for (uint8_t i = 0; i < NODE_COUNT; i++) {
    if (pgm_read_byte(&NODES[i].len) == len && pgm_read_byte(&NODES[i].bits) == bits) return i;
  }
  return NO_NODE;
}

bool buttonDown() { return digitalRead(BUTTON_PIN) == LOW; }

// wait until the button state is stable; returns that state
bool debouncedState() {
  bool s = buttonDown();
  unsigned long t = millis();
  while (millis() - t < DEBOUNCE_MS) {
    if (buttonDown() != s) { s = buttonDown(); t = millis(); }
  }
  return s;
}

void blink(int8_t idx) {
  for (uint8_t i = 0; i < BLINK_COUNT; i++) {
    lightNode(idx); delay(BLINK_ON_MS);
    allOff();       delay(BLINK_OFF_MS);
  }
}

void wakeISR() {
  detachInterrupt(digitalPinToInterrupt(BUTTON_PIN));
  wokeUp = true;
}

void goToSleep() {
  allOff();
  while (debouncedState()) {}              // make sure the button is released
  uint8_t adcsra = ADCSRA;
  ADCSRA = 0;                               // ADC off
  set_sleep_mode(SLEEP_MODE_PWR_DOWN);
  noInterrupts();
  wokeUp = false;
  EIFR = bit(INTF0);
  attachInterrupt(digitalPinToInterrupt(BUTTON_PIN), wakeISR, LOW);  // level interrupt wakes from power-down
  sleep_enable();
  sleep_bod_disable();
  interrupts();
  sleep_cpu();
  sleep_disable();
  ADCSRA = adcsra;
  while (debouncedState()) {}              // the waking press only wakes the board
}

uint8_t codeLen = 0;
uint8_t codeBits = 0;
bool    codeValid = true;
unsigned long lastActivity = 0;

void resetToStart() {
  codeLen = 0; codeBits = 0; codeValid = true;
  lightNode(START_NODE);
}

void setup() {
  for (uint8_t p = 4; p <= 13; p++) pinMode(p, INPUT_PULLUP);  // unused pins: no floating inputs
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  allOff();
  power_spi_disable();
  power_twi_disable();
  power_usart0_disable();
  resetToStart();
  lastActivity = millis();
}

void loop() {
  unsigned long now = millis();

  if (debouncedState()) {                    // button pressed
    unsigned long pressStart = millis();
    while (debouncedState()) {}
    unsigned long pressLen = millis() - pressStart;
    bool dash = pressLen >= DASH_THRESHOLD_MS;
    if (codeValid && codeLen < MAX_CODE_LEN) {
      if (dash) codeBits |= (1 << codeLen);
      codeLen++;
      int8_t n = findNode(codeLen, codeBits);
      if (n == NO_NODE) { codeValid = false; allOff(); }
      else lightNode(n);
    } else {
      codeValid = false; allOff();
    }
    lastActivity = millis();
    return;
  }

  if (codeLen > 0 && now - lastActivity >= CHAR_GAP_MS) {   // end of character
    if (codeValid) blink(findNode(codeLen, codeBits));
    else blink(START_NODE);
    resetToStart();
    lastActivity = millis();   // idle time counts from the end of the character
    return;
  }

  if (codeLen == 0 && now - lastActivity >= IDLE_SLEEP_MS) {
    goToSleep();
    resetToStart();            // on wake light Start
    lastActivity = millis();
  }
}
9

Set the fuses and upload

Do not use Burn Bootloader: the Pro board setting expects a crystal, and this board has none. Hold an ISP programmer's 2x3 pins on J1 and set the internal 8 MHz clock: avrdude -c usbasp -p m328p -U lfuse:w:0xE2:m -U hfuse:w:0xD9:m -U efuse:w:0xFF:m. Then, in the Arduino IDE, use Sketch > Upload Using Programmer.

Ibikoresho bikenewe:

Igikoresho cyandika porogaramu AVR ISPIgikoresho cyandika porogaramu AVR ISP
Mudasobwa Ifite Arduino IDEMudasobwa Ifite Arduino IDE
10

Print the back shell

An open-front tray, 92.6 x 66.6 x 8.3 mm, with four standoffs for M2 screws, a notch and floor opening to slide the cell out and an opening under J1. PLA, 0.2 mm layers, 20 % infill, printed on its floor.
Dosiye y'IgishushanyoSTLCC0 - Free
Kuramo icyitegererezo
11

Fit the shell

The standoffs hold the board 6.7 mm above the floor: measure your cell holder with a cell in it before you print. Check the holder's open end faces the board's bottom edge, where the shell's cell notch is. Slide in a CR2032 and screw the board into the shell with four M2 x 8 self-tapping screws.

Ibikoresho by'iyi ntambwe:

Umugozi wa PLAUmugozi wa PLA1 igice
Vise yikorera umurongoVise yikorera umurongo4 ibice
Bateri y'igiceri CR2032Bateri y'igiceri CR20321 igice

Ibikoresho bikenewe:

Imashini icapa 3D ikoresha umugozi (FDM)Imashini icapa 3D ikoresha umugozi (FDM)
Kalipe ya VernierKalipe ya Vernier
Agatsiko ka tuneviza nyayoAgatsiko ka tuneviza nyayo
12

Troubleshooting

Pocket Morse decoder troubleshooting.

Flow

Loading...
13

History and honest limits

The letters and figures follow **Dave Nathanson**'s (KG6ZJO) complete chart of 2011, shared as copyleft. Where the signs sit is ours; their codes are ITU-R M.1677-1's. The board, sizes, parts and timings are ours, drawn with Youblob's Draw PCB: its ERC and DRC pass with no errors and every LED's wiring, code and label was checked against the firmware by script, but it has not been built, flashed or tested.

Ibikoresho

12

Ibikoresho bikenewe

12

Dosiye z'igishushanyo

1

Iki gishushanyo gikora

Thumbnail
Agateganyo

Igisobanuzi cya Kode ya Morse

Free

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Blueprint zijyanye

Izi blueprint zisangira ubumenyi — uburyo, ibikoresho cyangwa amahame

Pocket Morse Code Learning Board - v.1

Pocket Morse Code Learning Board - v.1

na Admiral OOMNO

Ibikoresho by'Amashanyarazi

1
0
0
0
0
0
Morse Code

Morse Code

na PixelFI

IKORANABUHANGA

46
0
0
0
0
0
Morse Telegraph

Morse Telegraph

na EdFI

IKORANABUHANGA

65
0
0
0
1
0

CC0 Umurenge rusange

Iyi blueprint yasohowe munsi ya CC0. Ushobora gukoporora, guhindura, gukwirakwiza no gukoresha nta kwemererwa.

Shyigikira Umuremyi ugura ibicuruzwa binyuze muri Blueprint ye Komisiyo y'Umuremyi byashyizweho n'Abacuruzi, cyangwa kora verisiyo nshya y'iyi Blueprint ukayinjiza nk'isano muri Blueprint yawe kugira ngo musangire inyungu.

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