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Get Started Examples

[English]

本示例演示了如何通过两个 ESP32 芯片之间的通信获取 CSI 数据，并使用图形界面显示 CSI 子载波的实时数据。

硬件

您需要准备两块开发板，一块作为发送方，一块作为接收方。

example_display

为了保证 CSI 的感知效果，请尽量满足以下要求：

  1. 使用 ESP32-C5 / ESP32-S6：ESP32-C5 支持双频WIFI通讯，是目前最好的射频芯片，ESP32-C6是目前已上市芯片中最好的射频芯片。
  2. 使用外部天线：PCB 天线的方向性较差，容易受到主板干扰。
  3. 两个设备之间的距离应大于 1 米。

绑定

  1. 分别烧录 csi_recv and csi_send 到两块 ESP32 上。

    device_log

    # csi_send
cd esp-csi/examples/get-started/csi_send
idf.py set-target esp32c3
idf.py flash -b 921600 -p /dev/ttyUSB0 monitor

# csi_recv
cd esp-csi/examples/get-started/csi_recv
idf.py set-target esp32c3
idf.py flash -b 921600 -p /dev/ttyUSB1

  2. 在 csi_recv 里运行 csi_data_read_parse.py 做数据分析。 在运行前请关闭 idf.py monitor 。

    cd esp-csi-gitlab/examples/get-started/tools

# Install python related dependencies
pip install -r requirements.txt

# Graphical display
python csi_data_read_parse.py -p /dev/ttyUSB1

CSI 数据格式

以一行 CSI raw data 为例：

type,id,mac,rssi,rate,sig_mode,mcs,bandwidth,smoothing,not_sounding,aggregation,stbc,fec_coding,sgi,noise_floor,ampdu_cnt,channel,secondary_channel,local_timestamp,ant,sig_len,rx_state,len,first_word,data CSI_DATA,0,94:d9:b3:80:8c:81,-30,11,1,6,1,0,1,0,1,0,0,-93,0,13,2,2751923,0,67,0,128,1,"[67,48,4,0,0,0,0,0,0,0,5,0,20,1,20,1,19,0,17,1,16,2,15,2,14,1,12,0,12,-1,12,-3,12,-4,13,-6,15,-7,16,-8,16,-8,16,-8,16,-6,15,-5,15,-4,14,-4,13,-4,12,-4,11,-4,10,-4,9,-5,8,-6,4,-4,8,-9,9,-10,9,-10,10,-11,11,-10,11,-10,12,-9,11,-8,11,-7,10,-6,9,-6,7,-6,6,-7,5,-7,5,-8,5,-9,5,-10,5,-11,5,-11,6,-11,7,-11,8,-11,9,-10,9,-9,8,-8,8,-7,1,-2,0,0,0,0,0,0,0,0]"

esp32-c5 和 esp32-c6 为：

type,seq,mac,rssi,rate,noise_floor,fft_gain,agc_gain,channel,local_timestamp,sig_len,rx_state,len,first_word,data CSI_DATA,7,1a:00:00:00:00:00,-23,11,-96,32,4,11,372852,47,0,256,0,"[0,0,0,0,0,0,0,0,0,0,0,0,-6,-13,-6,-14,-3,-15,-2,-16,-2,-18,-3,-17,-1,-18,2,-19,0,-21,3,-21,1,-20,4,-21,4,-23,6,-22,7,-21,8,-23,9,-23,10,-21,10,-22,11,-20,12,-19,11,-25,13,-22,12,-23,14,-23,14,-22,14,-21,13,-21,13,-19,14,-22,14,-19,14,-23,16,-22,14,-22,13,-22,14,-21,13,-22,13,-23,13,-23,12,-26,13,-24,13,-24,12,-25,14,-29,13,-26,14,-26,15,-26,13,-27,15,-28,16,-27,14,-30,15,-28,16,-28,18,-27,16,-31,18,-31,19,-31,0,0,0,0,0,0,-29,-23,-28,-21,-30,-18,-26,-20,-30,-21,-25,-23,-26,-21,-25,-22,-26,-19,-22,-22,-24,-19,-22,-20,-24,-20,-24,-18,-23,-18,-22,-18,-25,-17,-23,-18,-21,-18,-21,-17,-24,-14,-22,-16,-21,-14,-22,-15,-21,-19,-23,-16,-22,-17,-23,-13,-23,-16,-25,-15,-21,-17,-22,-15,-21,-17,-23,-16,-20,-16,-21,-20,-21,-19,-21,-19,-19,-20,-17,-20,-18,-20,-16,-21,-15,-21,-15,-20,-13,-21,-11,-20,-10,-20,-11,-19,-9,-20,-8,-22,-6,-19,-7,-20,-4,-19,-2,-18,-2,-18,1,-17,4,-18,0,0,0,0,0,0,0,0,0,0]"

  • 元数据字段：包括 type, id, mac, ... first_word等。
  • CSI 数据：由最后一项 data 数组存储，用 [...] 框起。包含每个子载波的信道状态信息。具体结构可参考 ESP-WIFI-CSI Guide 的 Long Training Field (LTF) 部分。对于每一个子载波，先储存虚数部分，再储存实数部分（即：[子载波1的虚部，子载波1的实部，子载波2的虚部，子载波2的实部，子载波3的虚部，子载波3的实部，...]）。

LTF的顺序为：LLTF、HT-LTF、STBC-HT-LTF。根据通道和分组信息，可能不会出现所有3个LTF。 he order of LTF is: LLTF, HT-LTF, STBC-HT-LTF. Depending on the channel and grouping information, not all 3 LTFs may appear.

A&Q

1. csi_send 打印无内存

  • 现象：串口上出现以下日志：
  W (510693) csi_send:  ESP-NOW 发送错误
  • 原因：当前信道拥堵，导致发送数据包时出现拥堵，ESP-NOW 缓冲区空间满
  • 解决方案：更换 Wi-Fi 信道或更换到网络环境更好的地方

2. csi_data_read_parse.py 串口打印异常

  • 现象：串口上出现以下日志：
  element number is not equal
  data is not incomplete
  • 原因：绘图时 PYQT 占用大量 CPU，导致 PC 无法及时读取串口缓冲队列，造成数据混乱
  • 解决方案：提高串口的波特率