split main .ino fine into multiple sub files

pong_player.cpp

@@ -0,0 +1,33 @@
+#include <Arduino.h>
+#include "config.h"
+
+int ball_player_collision(int player, int ball_y) {
+  for (int p= player; p < player + BAR_LENGTH; p++) {
+    if (ball_y == p) {
+      return 1;
+    }
+  }
+  return 0;
+}
+
+int pong_move_p1(int &p1_start, int &need_refresh) {
+  if (digitalRead(P1_BTN_UP) == LOW && p1_start > 0) {
+    p1_start -= 1;
+    need_refresh= 1;
+  }
+  else if (digitalRead(P1_BTN_BOTTOM) == LOW && p1_start < 5) {
+    p1_start += 1;
+    need_refresh= 1;
+  }
+}
+
+int pong_move_p2(int &p2_start, int &need_refresh) {
+  if (digitalRead(P2_BTN_UP) == LOW && p2_start > 0) {
+    p2_start -= 1;
+    need_refresh= 1;
+  }
+  else if (digitalRead(P2_BTN_BOTTOM) == LOW && p2_start < 5) {
+    p2_start += 1;
+    need_refresh= 1;
+  }
+}