基于lora基站与蓝牙信标技术在养老院人员定位系统中的实战应用

智能终端设备代码片段
#include <stdio.h>
        
        // 定时扫描蓝牙信标
        if (current_time - last_scan_time >= SCAN_INTERVAL / 1000) {
            scan_beacons();
        }
        
        // 定时上传数据
        if (current_time - last_upload_time >= UPLOAD_INTERVAL / 1000) {
            upload_data();
        }
        
        // 短延时，降低CPU占用
        delay_ms(100);
    }
}

// 程序入口
int main() {
    printf("Smart Terminal Starting...\n");
    printf("Device ID: %s\n", DEVICE_ID);
    
    // 初始化设备
    device_init();
    
    // 进入主循环
    main_loop();
    
    return 0;
}

// 数据序列化函数
int serialize_position_data(PositionData *data, char *buffer, int buffer_size) {
    if (!data || !buffer || buffer_size <= 0) {
        return -1;
    }
    
    // 简单JSON格式序列化
    int len = snprintf(buffer, buffer_size, 
        "{\"device_id\":\"%s\",\"beacon_count\":%d,\"beacons\":[",
        data->device_id, data->beacon_count);
    
    if (len <= 0 || len >= buffer_size) {
        return -1;
    }
    
    // 添加信标数据
    for (int i = 0; i < data->beacon_count; i++) {
        char beacon_str[128];
        int beacon_len = snprintf(beacon_str, sizeof(beacon_str),
            "{\"uuid\":\"%s\",\"rssi\":%d,\"tx_power\":%d,\"timestamp\":%ld}",
            data->beacons[i].uuid,
            data->beacons[i].rssi,
            data->beacons[i].tx_power,
            data->beacons[i].timestamp);
        
        if (beacon_len <= 0 || beacon_len >= sizeof(beacon_str)) {
            return -1;
        }
        
        // 检查缓冲区是否足够
        if (len + beacon_len + 2 >= buffer_size) {
            return -1;
        }
        
        // 添加到缓冲区
        strcat(buffer, beacon_str);
        len += beacon_len;
        
        // 添加分隔符
        if (i < data->beacon_count - 1) {
            strcat(buffer, ",");
            len++;
        }
    }
    
    // 添加结尾部分
    char end_str[64];
    int end_len = snprintf(end_str, sizeof(end_str),
        "],\"battery\":%.1f,\"upload_time\":%ld}",
        data->battery, data->upload_time);
    
    if (end_len <= 0 || end_len >= sizeof(end_str)) {
        return -1;
    }
    
    // 检查缓冲区是否足够
    if (len + end_len >= buffer_size) {
        return -1;
    }
    
    // 添加到缓冲区
    strcat(buffer, end_str);
    len += end_len;
    
    return len;
}