diff --git a/src/unitdev04/change_mode.py b/src/unitdev04/change_mode.py
new file mode 100644
index 0000000..53c96f3
--- /dev/null
+++ b/src/unitdev04/change_mode.py
@@ -0,0 +1,109 @@
+import curses
+import serial
+import struct
+from pymavlink.dialects.v20 import ardupilotmega as mavlink2
+
+PORT = "COM5" # or "/dev/ttyUSB0"
+BAUD = 57600
+target_system = 5
+target_component = 1
+MAV_CMD_DO_SET_MODE = 176
+
+mode_list = [
+    ("STABILIZE", 0),
+    ("AUTO", 3),
+    ("GUIDED", 4),
+    ("LOITER", 5)
+]
+
+ser = serial.Serial(PORT, BAUD)
+
+class PacketCapture:
+    def __init__(self):
+        self.data = bytearray()
+    def write(self, b):
+        self.data.extend(b)
+        return len(b)
+
+def build_api_tx_frame(data: bytes, frame_id=0x01):
+    frame_type = 0x10
+    dest_addr64 = b'\x00\x00\x00\x00\x00\x00\xFF\xFF'  # 廣播
+    dest_addr16 = b'\xFF\xFE'
+    broadcast_radius = 0x00
+    options = 0x00
+
+    frame = struct.pack(">B", frame_type) + struct.pack(">B", frame_id)
+    frame += dest_addr64 + dest_addr16
+    frame += struct.pack(">BB", broadcast_radius, options) + data
+    checksum = 0xFF - (sum(frame) & 0xFF)
+    return b'\x7E' + struct.pack(">H", len(frame)) + frame + struct.pack("B", checksum)
+
+def curses_main(stdscr):
+    curses.curs_set(0)
+    selected = 0
+
+    while True:
+        stdscr.clear()
+        h, w = stdscr.getmaxyx()
+
+        stdscr.addstr(1, 2, "模式選單（使用:箭頭選擇，Enter:發送，q:離開）")
+
+        for i, (name, _) in enumerate(mode_list):
+            if i == selected:
+                stdscr.attron(curses.A_REVERSE)
+                stdscr.addstr(i + 3, 4, f"> {name}")
+                stdscr.attroff(curses.A_REVERSE)
+            else:
+                stdscr.addstr(i + 3, 4, f"  {name}")
+
+        key = stdscr.getch()
+
+        if key == curses.KEY_UP:
+            selected = (selected - 1) % len(mode_list)
+        elif key == curses.KEY_DOWN:
+            selected = (selected + 1) % len(mode_list)
+        elif key in [10, 13]:  # Enter
+            name, custom_mode = mode_list[selected]
+            capture = PacketCapture()
+            mav = mavlink2.MAVLink(capture, srcSystem=1, srcComponent=1)
+            mav.version = 2
+
+            msg = mav.command_long_encode(
+                target_system=target_system,
+                target_component=target_component,
+                command=MAV_CMD_DO_SET_MODE,
+                confirmation=0,
+                param1=1,
+                param2=custom_mode,
+                param3=0, param4=0, param5=0, param6=0, param7=0
+            )
+            print("msg =", msg)  # 確認封包物件生成
+
+            mav.send(msg)  # 改為 send() 會寫入 capture
+            print("RAW HEX:", capture.data.hex())
+
+            api_frame = build_api_tx_frame(capture.data)
+            ser.write(api_frame)
+
+            # 顯示封包資訊
+            msg_line = min(h - 4, len(mode_list) + 5)
+            stdscr.addstr(msg_line, 2, f"發送模式切換：{name} ({custom_mode})")
+            stdscr.addstr(msg_line + 1, 2, f"MAVLink HEX: {' '.join(f'{b:02x}' for b in capture.data)[:w-4]}")
+            stdscr.addstr(msg_line + 2, 2, f"XBee API HEX: {' '.join(f'{b:02x}' for b in api_frame)[:w-4]}")
+            stdscr.refresh()
+            curses.napms(1500)
+
+        elif key in [ord('q'), ord('Q')]:
+            break
+
+        stdscr.refresh()
+
+
+try:
+    curses.wrapper(lambda stdscr: curses_main(stdscr))  # 使用 lambda 函數來傳遞 ser
+
+except Exception as e:
+    print(f"發生錯誤: {e}")
+finally:
+    ser.close()
+    print("程式結束，串口已關閉")
diff --git a/src/unitdev04/endpoint_at.py b/src/unitdev04/endpoint_at.py
index b6e0bfb..21c53f4 100644
--- a/src/unitdev04/endpoint_at.py
+++ b/src/unitdev04/endpoint_at.py
@@ -38,4 +38,4 @@ try:
         pass
 except KeyboardInterrupt:
     print("\nProgram terminated.")
-    ser.close()
+    ser.close()
\ No newline at end of file
diff --git a/src/unitdev04/receive.py b/src/unitdev04/receive.py
new file mode 100644
index 0000000..eab6436
--- /dev/null
+++ b/src/unitdev04/receive.py
@@ -0,0 +1,60 @@
+from xbee import XBee
+import serial
+from pymavlink import mavutil
+import time
+
+# 配置 XBee 串口連接
+ser = serial.Serial('COM5', 57600)  # XBee 串口
+
+
+# 無人機系統 ID（假設為 5）和目標系統 ID（假設為 1）
+system_id = 5
+target_system_id = 1  # 設定目標系統 ID，這裡假設目標系統 ID 是 1
+
+# 目標設備的 64 位地址（請替換為實際的無人機地址）
+target_address = b'\x00\x13\xa2\x00\x40\x5f\x88\x56'  # 例如：00 13 A2 00 40 5F 88 56
+
+def decode_mavlink_data(data,master):
+    """解碼 MAVLink 的原始數據並處理 HEARTBEAT 訊息"""
+
+    try:
+        msg = master.parse_char(data)
+        if msg:
+            if msg.get_type() == "HEARTBEAT":
+                print(f"Raw MAVLink Data (Hex): {data.hex()}")
+                print(f"Received MAVLink message: {msg}")
+                print(f"System status: {msg.system_status}")
+                print(f"Flight mode: {mavutil.mode_string_v10(msg)}")
+                print(f"System ID: {msg.get_srcSystem()}")  # 使用 get_srcSystem() 獲取 system_id
+    except Exception as e:
+        print(f"Failed to decode MAVLink data: {e}")
+
+def receive_packets(ser):
+    xbee = XBee(ser)
+    # 創建 MAVLink 解析器並與 XBee 串口連接
+    master = mavutil.mavlink.MAVLink(ser)
+
+    while True:
+        try:
+            # 從 XBee 接收數據
+            xbee_data = xbee.wait_read_frame()
+
+            # 讀取 `rf_data` 而非 `payload`
+            raw_data = xbee_data.get('rf_data', None)
+            if raw_data is None:
+                print("Warning: No 'rf_data' found in received XBee data!")
+                continue  # 跳過此次循環
+
+            # 解碼 MAVLink 訊息
+            decode_mavlink_data(raw_data,master)
+
+            # 根據需要觸發模式切換，例如根據用戶輸入更改模式
+            
+
+        except KeyboardInterrupt:
+            print("Exiting...")
+            break
+        except Exception as e:
+            print(f"Error: {e}")
+        
+        time.sleep(0.1)