【ESP32C2 ESP-IDF温度振动传感器详细设计】

ESP32C2 ESP-IDF温度振动传感器详细设计

硬件选型

1. 主控芯片：ESP32C2（集成WiFi和BLE，低功耗设计）
2. 温度传感器：DS18B20（数字输出，±0.5℃精度）或DHT22（需注意ESP32C2的GPIO电压兼容性）
3. 振动传感器：SW-420（机械式振动开关）或ADXL345（数字三轴加速度计，需I2C接口）
4. 供电模块：3.3V LDO稳压器（如AMS1117-3.3），支持锂电池充放电管理
5. 其他：10K上拉电阻（DS18B20）、0.1μF去耦电容

硬件连接

• DS18B20数据线接GPIO4，外接4.7K上拉电阻
• ADXL345的SCL接GPIO5，SDA接GPIO6（I2C默认引脚）
• SW-420输出接GPIO7，通过比较器转换为数字信号

---

代码实现（ESP-IDF V5.0+）

传感器数据采集

// DS18B20配置（需安装OneWire组件）
#include <ds18b20.h>
#define DS18B20_GPIO 4
ds18b20_handle_t temp_sensor;

void init_temperature_sensor() {
    ds18b20_config_t cfg = { .bus = DS18B20_GPIO };
    ds18b20_new_sensor(&cfg, &temp_sensor);
}

float read_temperature() {
    float temp;
    ds18b20_get_temperature(temp_sensor, &temp);
    return temp;
}

// ADXL345配置
#include <adxl345.h>
adxl345_handle_t accel;

void init_vibration_sensor() {
    i2c_config_t i2c_cfg = {
        .mode = I2C_MODE_MASTER,
        .sda_io_num = 6,
        .scl_io_num = 5,
        .sda_pullup_en = GPIO_PULLUP_ENABLE,
        .scl_pullup_en = GPIO_PULLUP_ENABLE
    };
    i2c_param_config(I2C_NUM_0, &i2c_cfg);
    adxl345_new_sensor(I2C_NUM_0, ADXL345_ADDR, &accel);
}

void read_vibration(int16_t *x, int16_t *y, int16_t *z) {
    adxl345_get_acceleration(accel, x, y, z);
}

---

MQTT数据上传

1. 配置MQTT客户端：

#include <mqtt_client.h>
esp_mqtt_client_handle_t mqtt_client;

void mqtt_event_handler(void *handler_args, esp_event_base_t base, 
                        int32_t event_id, void *event_data) {
    esp_mqtt_event_handle_t event = event_data;
    switch(event->event_id) {
        case MQTT_EVENT_CONNECTED:
            esp_mqtt_client_subscribe(mqtt_client, "device/ota", 0);
            break;
        case MQTT_EVENT_DATA:
            // 处理OTA指令
            break;
    }
}

void init_mqtt() {
    esp_mqtt_client_config_t mqtt_cfg = {
        .uri = "mqtt://broker.emqx.io",
        .username = "device_001",
        .password = "your_password"
    };
    mqtt_client = esp_mqtt_client_init(&mqtt_cfg);
    esp_mqtt_client_register_event(mqtt_client, ESP_EVENT_ANY_ID, mqtt_event_handler, NULL);
    esp_mqtt_client_start(mqtt_client);
}

2. 发布传感器数据：

void publish_sensor_data() {
    cJSON *payload = cJSON_CreateObject();
    cJSON_AddNumberToObject(payload, "temp", read_temperature());
    
    int16_t x,y,z;
    read_vibration(&x, &y, &z);
    cJSON_AddNumberToObject(payload, "vib_x", x);
    cJSON_AddNumberToObject(payload, "vib_y", y);
    cJSON_AddNumberToObject(payload, "vib_z", z);

    char *json_str = cJSON_PrintUnformatted(payload);
    esp_mqtt_client_publish(mqtt_client, "sensor/data", json_str, 0, 1, 0);
    cJSON_Delete(payload);
    free(json_str);
}

---

OTA升级实现

1. HTTP服务器端准备：

   • 将固件.bin文件放置在Web服务器（如Nginx）的/ota/firmware.bin
   • 提供版本信息接口/ota/version.json

2. ESP32C2端代码：

#include <esp_https_ota.h>

void check_ota_update() {
    esp_http_client_config_t http_cfg = {
        .url = "http://your-server.com/ota/version.json",
        .cert_pem = NULL  // 若用HTTPS需配置证书
    };
    
    esp_http_client_handle_t client = esp_http_client_init(&http_cfg);
    esp_http_client_perform(client);
    
    int firmware_ver = esp_http_client_get_status_code(client);
    if (firmware_ver > CURRENT_FIRMWARE_VERSION) {
        start_ota_update();
    }
    esp_http_client_cleanup(client);
}

void start_ota_update() {
    esp_http_client_config_t ota_cfg = {
        .url = "http://your-server.com/ota/firmware.bin",
    };
    esp_https_ota_config_t ota_config = {
        .http_config = &ota_cfg,
    };
    esp_https_ota_handle_t ota_handle = NULL;
    esp_https_ota_begin(&ota_config, &ota_handle);
    
    while (1) {
        esp_err_t err = esp_https_ota_perform(ota_handle);
        if (err == ESP_ERR_HTTPS_OTA_IN_PROGRESS) continue;
        if (err == ESP_OK) {
            esp_https_ota_finish(ota_handle);
            esp_restart();
        } else {
            ESP_LOGE("OTA", "Update failed!");
            break;
        }
    }
}

---

数据库存储设计（MQTT Broker端）

1. EMQX Broker配置：

   • 启用规则引擎，创建规则：

   SELECT 
       payload.temp as temperature,
       payload.vib_x as vibration_x,
       payload.timestamp as timestamp
   FROM "sensor/data"
   

   • 添加动作：存储到MySQL/PostgreSQL/MongoDB
   • 配置SQL模板：

   INSERT INTO sensor_data 
   (device_id, temperature, vibration, timestamp)
   VALUES (
       ${clientid}, 
       ${temperature}, 
       JSON_ARRAY(${vibration_x}, ${vibration_y}, ${vibration_z}),
       FROM_UNIXTIME(${timestamp}/1000)
   )
   

2. 数据库表结构：

CREATE TABLE sensor_data (
    id INT AUTO_INCREMENT PRIMARY KEY,
    device_id VARCHAR(32) NOT NULL,
    temperature FLOAT,
    vibration JSON,
    timestamp DATETIME,
    INDEX(device_id, timestamp)
);

---

关键注意事项

1. ESP32C2的GPIO电压为3.3V，需确保传感器兼容
2. 低功耗设计建议：
   • 使用esp_sleep_enable_timer_wakeup()实现定时唤醒
   • 采集后立即进入Deep Sleep模式
3. OTA更新时需预留至少2个分区（ota_0/ota_1）
4. MQTT消息建议添加时间戳：

   cJSON_AddNumberToObject(payload, "timestamp", esp_log_timestamp());