Add keyer logic to Arduino

keyer/keyer.ino

@@ -0,0 +1,49 @@
+const int dot_pin = 2;
+const int dash_pin = 3;
+
+float wpm = 10.0f;
+
+char state = 'R'; // Ready, Send, Wait
+int remaining = 0;
+int last_update = -1;
+
+char last_send = 'X';
+
+void setup() {
+  Serial.begin(115200); 
+
+  pinMode(dot_pin, INPUT_PULLUP);
+  pinMode(dash_pin, INPUT_PULLUP);
+}
+
+void loop() {
+  int dit = 60.0f / (50.0f * wpm) * 1000.0f;
+  
+  int dt = millis() - last_update;
+  last_update = millis();
+  remaining -= dt;
+
+  if (state == 'S' && remaining <= 0) {
+    state = 'W';
+    remaining = dit;
+  } else if (state == 'W' && remaining <= 0) {
+    state = 'R';
+  } else if (state == 'R') {
+    if (digitalRead(dot_pin) == LOW) {
+      state = 'S';
+      remaining = dit;
+    }
+    if (digitalRead(dash_pin) == LOW) {
+      state = 'S';
+      remaining = 3 * dit;
+    }
+  }
+
+  char current_send = state == 'S' ? '2' : '0';
+  
+  if (current_send != last_send) {
+    Serial.print(current_send);
+    last_send = current_send;
+  }
+  delay(1); // Limit update rate under 1kHz
+}