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# MQTT AT命令集
AT+QMTCFG="version",3,4 # 设置MQTT版本（3:3.1.1, 4:5.0）
AT+QMTCFG="aliauth",1,"client1","username","password"
AT+QMTCFG="ssl",1,1 # 启用SSL
AT+QMTOPEN=0,"broker.example.com",1883 # 打开连接
AT+QMTCONN=0,"client123" # 连接Broker
AT+QMTSUB=0,1,"sensor/temp",1 # 订阅主题
AT+QMTPUBEX=0,1,1,0,"control/light","{"state":"on"}" # 发布消息
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# Python控制蜂窝模组MQTT的示例
import serial
import time
import json
class CellularMQTTClient:
def __init__(self, port="/dev/ttyUSB2", baudrate=115200):
self.ser = serial.Serial(port, baudrate, timeout=1)
self.client_id = f"device_{int(time.time())}"
def send_at(self, command, expected="OK", timeout=2):
"""发送AT命令并等待响应"""
self.ser.write(f"{command}\r\n".encode())
time.sleep(0.1)
start_time = time.time()
response = ""
while time.time() - start_time < timeout:
if self.ser.in_waiting:
line = self.ser.readline().decode().strip()
response += line + "\n"
if expected in line:
return True, response
if "ERROR" in line:
return False, response
return False, response
def setup_mqtt(self, broker, port=1883):
"""配置MQTT连接"""
steps = [
# 1. 检查模组就绪
("AT", "OK"),
# 2. 设置MQTT版本
('AT+QMTCFG="version",3,4', "OK"),
# 3. 配置SSL/TLS（可选）
('AT+QMTCFG="ssl",1,1', "OK"),
# 4. 打开连接
(f'AT+QMTOPEN=0,"{broker}",{port}', "+QMTOPEN: 0,0"),
# 5. 等待连接建立
("", "+QMTOPEN: 0,0"),
]
for cmd, expected in steps:
if cmd:
success, resp = self.send_at(cmd, expected)
if not success:
print(f"步骤失败: {cmd}")
return False
time.sleep(1)
return True
def connect_broker(self, username=None, password=None):
"""连接MQTT Broker"""
# 准备连接参数
client_id = self.client_id
keepalive = 60
cleansession = 1
cmd = f'AT+QMTCONN=0,"{client_id}",{keepalive},{cleansession}'
if username and password:
cmd = f'AT+QMTCONN=0,"{client_id}",{keepalive},{cleansession},"{username}","{password}"'
success, resp = self.send_at(cmd, "+QMTCONN: 0,0,0")
if success:
print(f"MQTT连接成功，ClientID: {client_id}")
return True
else:
print("MQTT连接失败")
return False
def subscribe(self, topic, qos=1):
"""订阅主题"""
cmd = f'AT+QMTSUB=0,1,"{topic}",{qos}'
success, resp = self.send_at(cmd, "+QMTSUB: 0,1,0")
return success
def publish(self, topic, payload, qos=1, retain=0):
"""发布消息"""
# 如果是字典，转换为JSON
if isinstance(payload, dict):
payload = json.dumps(payload)
# 注意：payload需要正确处理特殊字符
encoded_payload = payload.replace('"', '\\"')
cmd = f'AT+QMTPUBEX=0,{qos},{retain},0,"{topic}","{encoded_payload}"'
success, resp = self.send_at(cmd, "+QMTPUBEX: 0,0")
return success
def listen_for_messages(self, callback, timeout=30):
"""监听接收到的消息"""
start_time = time.time()
while time.time() - start_time < timeout:
if self.ser.in_waiting:
line = self.ser.readline().decode().strip()
# 解析MQTT消息
if "+QMTRECV: 0," in line:
# 格式: +QMTRECV: 0,<msgid>,<topic>,<payload>
parts = line.split(",")
if len(parts) >= 4:
msgid = parts[1]
topic = parts[2].strip('"')
payload = parts[3].strip('"')
# 调用回调函数处理消息
callback(topic, payload)
time.sleep(0.1)
def disconnect(self):
"""断开连接"""
self.send_at("AT+QMTDISC=0", "+QMTDISC: 0,0")
self.send_at("AT+QMTCLOSE=0", "+QMTCLOSE: 0,0")
self.ser.close()
# 使用示例
def on_message_received(topic, payload):
print(f"收到消息 - 主题: {topic}, 内容: {payload}")
# 解析JSON数据
try:
data = json.loads(payload)
print(f"温度: {data.get('temperature')}°C")
except:
print(f"原始数据: {payload}")
# 主程序
if __name__ == "__main__":
mqtt_client = CellularMQTTClient("/dev/ttyUSB2", 115200)
# 1. 配置MQTT
if mqtt_client.setup_mqtt("broker.hivemq.com", 1883):
# 2. 连接Broker
if mqtt_client.connect_broker():
# 3. 订阅主题
mqtt_client.subscribe("sensor/#")
mqtt_client.subscribe("control/#")
# 4. 发布设备信息
device_info = {
"device_id": "sensor_001",
"firmware": "1.0.0",
"status": "online",
"timestamp": time.time()
}
mqtt_client.publish("device/info", device_info)
# 5. 模拟传感器数据上报
for i in range(10):
sensor_data = {
"temperature": 25 + i * 0.5,
"humidity": 60 - i,
"battery": 85 - i,
"timestamp": time.time()
}
mqtt_client.publish("sensor/data", sensor_data, qos=1)
time.sleep(10)
# 6. 监听消息（非阻塞方式）
import threading
listen_thread = threading.Thread(
target=mqtt_client.listen_for_messages,
args=(on_message_received, 300) # 监听5分钟
)
listen_thread.start()
# 等待线程结束
listen_thread.join()
# 7. 断开连接
mqtt_client.disconnect()
