diff --git a/src/handler/mhz19_co2.py b/src/handler/mhz19_co2.py
new file mode 100644
index 0000000..74c4fde
--- /dev/null
+++ b/src/handler/mhz19_co2.py
@@ -0,0 +1,65 @@
+import serial
+
+
+class Mhz19Co2:
+    def __init__(self):
+        self.last_read = None
+
+        self.serial_port = "/dev/tty.usbserial-B001BTPZ"
+        self.baud_rate = 9600
+        self.byte_size = 8
+        self.parity = "N"
+        self.stop_bits = 1
+        self.timeout = None
+
+    def get_last_read(self):
+        if self.last_read is None:
+            return self.read()
+        return self.last_read
+
+    def read(self):
+        try:
+            ser = serial.Serial(
+                port=self.serial_port,
+                baudrate=self.baud_rate,
+                bytesize=self.byte_size,
+                parity=self.parity,
+                stopbits=self.stop_bits,
+                timeout=self.timeout,
+            )
+
+            # send "Read CO2" command
+            command_data = bytes([0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79])
+            ser.write(command_data)
+
+            # read "Return Value (CO2 concentration)"
+            data = ser.read(9)
+            # print("data[2]", data[2])
+            # print("data[3]", data[3])
+            # print("data[4]", data[4])
+            # print("data[5]", data[5])
+            # print("data[6]", data[6])
+            # print("data[7]", data[7])
+            # print("data[8]", data[8])
+
+            # show CO2 concentration
+            concentration = data[2] * 256 + data[3]
+            print(f"=== send data ===")
+            print(f"send: {command_data}")
+            print(f"=== read data ===")
+            print(f"data: {data}")
+            print(f"data[2] {data[2]}")
+            print(f"data[3] {data[3]}")
+            print(f"CO2 Concentration {concentration} ppm")
+            print(f"=== === ===")
+            print(f"")
+
+        except Exception as e:
+            print(f"Error reading data: {e}")
+        finally:
+            if ser:
+                ser.close()
+                ser = None
+
+        self.last_read = concentration
+        return concentration