STM32 + ESP8266 实现 MQTT 数据上报
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物联网项目中，单片机采集传感器数据后需要上传到云端。MQTT是物联网通信的标准协议，轻量且可靠。本文教你在STM32+ESP8266上实现MQTT数据上报。
硬件准备
所需材料
| 组件 | 数量 | 说明 |
|---|---|---|
| STM32F103C8T6 | 1 | 主控芯片 |
| ESP8266-01S | 1 | WiFi模块 |
| DHT11 | 1 | 温湿度传感器 |
| USB转TTL | 1 | 调试用 |
| 面包板+杜邦线 | 若干 | - |
连接图
STM32F103 ESP8266-01S
---------- -----------
PA9 (TX) ──────────── RX
PA10 (RX) ──────────── TX
3.3V ──────────── VCC
GND ──────────── GND
DHT11
----
DATA ──────────── PA6
VCC ──────────── 3.3V
GND ──────────── GND总体架构
┌─────────────┐ UART ┌─────────────┐ MQTT ┌─────────────┐
│ STM32F103 │ ─────────────── │ ESP8266 │ ────────── │ Broker │
│ (采集数据) │ │ (WiFi/MQTT) │ │ (云端) │
└─────────────┘ └─────────────┘ └─────────────┘
│ │
│ MQTT Topic: device/sensor │
└─────────────────────────────────────────────────────────┘MQTT 协议基础
核心概念
| 概念 | 说明 |
|---|---|
| Broker | MQTT服务器，负责消息转发 |
| Publisher | 发布者，向主题发送消息 |
| Subscriber | 订阅者，接收主题消息 |
| Topic | 主题，消息的分类路径 |
| QoS | 服务质量（0/1/2三个级别） |
常用 Topic 命名
device/{device_id}/temperature # 设备温度
device/{device_id}/humidity # 设备湿度
device/{device_id}/status # 设备状态STM32 代码实现
1. DHT11 驱动
// dht11.h
#ifndef __DHT11_H__
#define __DHT11_H__
#include "stm32f10x.h"
void DHT11_Init(void);
uint8_t DHT11_Read_Data(uint8_t *temp, uint8_t *humi);
#endif// dht11.c
#include "dht11.h"
#include "delay.h"
#define DHT11_PORT GPIOA
#define DHT11_PIN GPIO_Pin_6
void DHT11_Init(void) {
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
GPIO_InitStructure.GPIO_Pin = DHT11_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(DHT11_PORT, &GPIO_InitStructure);
}
void DHT11_Mode_Input(void) {
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = DHT11_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
GPIO_Init(DHT11_PORT, &GPIO_InitStructure);
}
void DHT11_Mode_Output(void) {
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = DHT11_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(DHT11_PORT, &GPIO_InitStructure);
}
uint8_t DHT11_Init_Sensor(void) {
uint8_t retry = 200;
DHT11_Mode_Output();
GPIO_ResetBits(DHT11_PORT, DHT11_PIN);
delay_ms(18);
GPIO_SetBits(DHT11_PORT, DHT11_PIN);
delay_us(30);
DHT11_Mode_Input();
while(GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN) && retry--) {
delay_us(1);
}
if(retry == 0) return 1;
retry = 200;
while(!GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN) && retry--) {
delay_us(1);
}
return (retry == 0) ? 1 : 0;
}
uint8_t DHT11_Read_Byte(void) {
uint8_t i, dat = 0;
for(i = 0; i < 8; i++) {
while(GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN));
delay_us(30);
dat <<= 1;
if(GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN)) {
dat |= 1;
}
while(!GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN));
}
return dat;
}
uint8_t DHT11_Read_Data(uint8_t *temp, uint8_t *humi) {
uint8_t buf[5];
uint8_t i;
if(DHT11_Init_Sensor()) return 1;
for(i = 0; i < 5; i++) {
buf[i] = DHT11_Read_Byte();
}
if(buf[0] + buf[1] + buf[2] + buf[3] == buf[4]) {
*humi = buf[0];
*temp = buf[2];
return 0;
}
return 1;
}2. ESP8266 MQTT 客户端
// esp8266_mqtt.h
#ifndef __ESP8266_MQTT_H__
#define __ESP8266_MQTT_H__
#include "stm32f10x.h"
#include "stdio.h"
#include "string.h"
#define MQTT_BROKER "broker.emqx.io" // 免费公共Broker
#define MQTT_PORT 1883
#define MQTT_CLIENT_ID "stm32_client_001"
#define MQTT_USER ""
#define MQTT_PASS ""
#define MQTT_KEEPALIVE 60
#define MQTT_QOS 0
void ESP8266_MQTT_Init(void);
uint8_t ESP8266_MQTT_Connect(void);
uint8_t ESP8266_MQTT_Publish(const char *topic, const char *payload);
void ESP8266_Send_Cmd(char *cmd, char *ack, uint16_t timeout);
#endif// esp8266_mqtt.c
#include "esp8266_mqtt.h"
#include "usart.h"
#include "delay.h"
extern UART_HandleTypeDef UART1_Handler;
char mqtt_buffer[512];
// 发送AT指令
void ESP8266_Send_Cmd(char *cmd, char *ack, uint16_t timeout) {
Usart_SendString(UART1, cmd);
while(timeout--) {
if(Usart_ReceiveByte(UART1, (uint8_t *)ack)) {
if(strstr(mqtt_buffer, ack)) {
memset(mqtt_buffer, 0, sizeof(mqtt_buffer));
return;
}
}
delay_ms(1);
}
}
// MQTT CONNECT包构建
void MQTT_Connect(void) {
uint16_t client_id_len = strlen(MQTT_CLIENT_ID);
uint16_t user_len = strlen(MQTT_USER);
uint16_t pass_len = strlen(MQTT_PASS);
uint8_t connect_packet[100];
uint16_t packet_len = 0;
// Fixed Header
connect_packet[packet_len++] = 0x10; // CONNECT
// Remaining Length (待计算)
// Variable Header
connect_packet[packet_len++] = 0x00; // Protocol Name Length
connect_packet[packet_len++] = 0x04;
connect_packet[packet_len++] = 'M';
connect_packet[packet_len++] = 'Q';
connect_packet[packet_len++] = 'T';
connect_packet[packet_len++] = 'T';
connect_packet[packet_len++] = 0x04; // Protocol Level 4
connect_packet[packet_len++] = 0x02; // Connect Flag
connect_packet[packet_len++] = 0x00; // Keep Alive MSB
connect_packet[packet_len++] = MQTT_KEEPALIVE;
// Payload
// Client ID
connect_packet[packet_len++] = (client_id_len >> 8) & 0xFF;
connect_packet[packet_len++] = client_id_len & 0xFF;
memcpy(&connect_packet[packet_len], MQTT_CLIENT_ID, client_id_len);
packet_len += client_id_len;
// User & Password (如果有)
if(user_len > 0) {
connect_packet[packet_len++] = (user_len >> 8) & 0xFF;
connect_packet[packet_len++] = user_len & 0xFF;
memcpy(&connect_packet[packet_len], MQTT_USER, user_len);
packet_len += user_len;
}
// 计算并设置Remaining Length
uint8_t remaining = packet_len - 2;
connect_packet[1] = remaining;
// 发送
for(uint16_t i = 0; i < packet_len; i++) {
Usart_SendByte(UART1, connect_packet[i]);
}
}
// MQTT PUBLISH包构建
void MQTT_Publish(const char *topic, const char *payload) {
uint16_t topic_len = strlen(topic);
uint16_t payload_len = strlen(payload);
uint16_t packet_len = 2 + topic_len + payload_len;
uint8_t packet[512];
uint16_t idx = 0;
// Fixed Header
packet[idx++] = 0x30; // PUBLISH
packet[idx++] = packet_len;
// Topic
packet[idx++] = (topic_len >> 8) & 0xFF;
packet[idx++] = topic_len & 0xFF;
memcpy(&packet[idx], topic, topic_len);
idx += topic_len;
// Payload
memcpy(&packet[idx], payload, payload_len);
idx += payload_len;
// 发送
for(uint16_t i = 0; i < idx; i++) {
Usart_SendByte(UART1, packet[i]);
}
}
uint8_t ESP8266_MQTT_Init(void) {
delay_ms(2000); // 等待上电稳定
ESP8266_Send_Cmd("AT+RST\r\n", "OK", 5000);
delay_ms(2000);
ESP8266_Send_Cmd("AT+CWMODE=1\r\n", "OK", 3000);
ESP8266_Send_Cmd("AT+CWJAP=\"你的WiFi\",\"密码\"\r\n", "OK", 10000);
return 0;
}
uint8_t ESP8266_MQTT_Connect(void) {
char cmd[100];
sprintf(cmd, "AT+CIPSTART=\"TCP\",\"%s\",%d\r\n", MQTT_BROKER, MQTT_PORT);
ESP8266_Send_Cmd(cmd, "CONNECT", 5000);
delay_ms(100);
MQTT_Connect();
return 0;
}
uint8_t ESP8266_MQTT_Publish(const char *topic, const char *payload) {
MQTT_Publish(topic, payload);
return 0;
}3. 主程序
// main.c
#include "stm32f10x.h"
#include "usart.h"
#include "delay.h"
#include "dht11.h"
#include "esp8266_mqtt.h"
char pub_topic[50];
char pub_payload[100];
int main(void) {
uint8_t temperature, humidity;
uint32_t last_publish = 0;
// 初始化
delay_init();
Usart1_Init(115200);
DHT11_Init();
printf("System Started!\r\n");
// 连接WiFi和MQTT Broker
ESP8266_MQTT_Init();
ESP8266_MQTT_Connect();
printf("MQTT Connected!\r\n");
while(1) {
// 每10秒上报一次
if(HAL_GetTick() - last_publish > 10000) {
if(DHT11_Read_Data(&temperature, &humidity) == 0) {
sprintf(pub_topic, "device/stm32/temperature");
sprintf(pub_payload, "{\"temp\":%d}", temperature);
ESP8266_MQTT_Publish(pub_topic, pub_payload);
sprintf(pub_topic, "device/stm32/humidity");
sprintf(pub_payload, "{\"humi\":%d}", humidity);
ESP8266_MQTT_Publish(pub_topic, pub_payload);
printf("Published: Temp=%d, Humi=%d\r\n", temperature, humidity);
}
last_publish = HAL_GetTick();
}
}
}Python 后端接收
使用Python快速搭建MQTT接收服务：
# mqtt_subscriber.py
import paho.mqtt.client as mqtt
import json
from datetime import datetime
def on_connect(client, userdata, flags, rc):
print(f"Connected with result code {rc}")
# 订阅主题
client.subscribe("device/stm32/#")
def on_message(client, userdata, msg):
timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
topic = msg.topic
payload = json.loads(msg.payload.decode())
print(f"[{timestamp}] Topic: {topic}")
print(f"[{timestamp}] Data: {payload}")
# 这里可以存入数据库
save_to_database(topic, payload)
def save_to_database(topic, data):
# 使用SQLite示例
import sqlite3
conn = sqlite3.connect('sensor_data.db')
cursor = conn.cursor()
cursor.execute('''
CREATE TABLE IF NOT EXISTS sensor_log (
id INTEGER PRIMARY KEY AUTOINCREMENT,
topic TEXT,
data TEXT,
timestamp DATETIME DEFAULT CURRENT_TIMESTAMP
)
''')
cursor.execute(
'INSERT INTO sensor_log (topic, data) VALUES (?, ?)',
(topic, str(data))
)
conn.commit()
conn.close()
# 创建客户端
client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
# 连接Broker
broker = "broker.emqx.io"
port = 1883
client.connect(broker, port, 60)
print("Starting MQTT Subscriber...")
client.loop_forever()测试验证
1. 运行Python接收端
python mqtt_subscriber.py2. 烧录STM32程序
使用ST-Link或J-Link烧录hex文件。
3. 观察数据
应该能看到类似输出：
[2026-03-27 21:30:01] Topic: device/stm32/temperature
[2026-03-27 21:30:01] Data: {'temp': 25}
[2026-03-27 21:30:01] Topic: device/stm32/humidity
[2026-03-27 21:30:01] Data: {'humi': 60}常见问题
1. AT指令无响应
- 检查TX/RX连接是否正确
- 确认波特率匹配（ESP8266默认115200）
- 检查电平是否匹配
2. WiFi连接失败
- 确认WiFi名称和密码正确
- 确保WiFi是2.4G频段（ESP8266不支持5G）
3. MQTT连接失败
- 确认Broker地址和端口正确
- 检查防火墙是否阻止1883端口
- 尝试使用公共测试Broker
进阶功能
心跳保活
// 每30秒发送MQTT PING包
void MQTT_Ping(void) {
uint8_t ping_packet[2] = {0xC0, 0x00};
for(int i = 0; i < 2; i++) {
Usart_SendByte(UART1, ping_packet[i]);
}
}OTA升级
可以通过MQTT接收固件更新指令，实现远程升级。
总结
本文实现了：
- ✅ STM32 DHT11传感器数据采集
- ✅ ESP8266 WiFi连接
- ✅ MQTT协议数据上报
- ✅ Python后端数据接收
完整的物联网数据采集链路搭建完成！
有问题欢迎留言讨论！