Add paddle sketch for Arduino

paddle/paddle.ino

@@ -0,0 +1,27 @@
+const int dot_pin = 2;
+const int dash_pin = 3;
+
+char last_state = 'X';
+
+void setup() {
+  Serial.begin(115200); 
+
+  pinMode(dot_pin, INPUT_PULLUP);
+  pinMode(dash_pin, INPUT_PULLUP);
+}
+
+void loop() {
+  char current_state = '0';
+  if (digitalRead(dot_pin) == LOW) {
+    current_state += 1;
+  }
+  if (digitalRead(dash_pin) == LOW) {
+    current_state += 2;
+  }
+  
+  if (current_state != last_state) {
+    Serial.print(current_state);
+    last_state = current_state;
+  }
+  delay(1); // Limit update rate under 1kHz
+}