使用Wio Terminal读取传感器的实时数据是在用Seeeduino V4.2开发板接收数据并把PC端作为服务端的基础上进行的,Wio Terminal作为客户端,在同一局域网下就可以访问传感器通过串口传送到服务器的数据。

下面是我在用Wio Terminal读取传感器实时数据的思路:

将Seeed-BME680获取的数据用WEB前端展示

用正则表达式整理串口传回的数据

使用Wio Terminal做HTTP请求并展示数据

1. 将Seeed-BME680获取的数据用WEB前端展示

在这里用Django可能会显得有点heavy,我的想法是在后期做一个数据管理端,做些数据分析什么的,所以这个Django项目我会继续完善。

我之前做的前端是以字符串的形式展示的:

这样其实不太好,如果这样写的话,Wio Terminal就要在做HTTP请求时把数据提取出来,导致刷新的时间过长

所以这里要做一些改进,把数据改成Json串:

import json

def index(request):

datas = getDatas()

content = {

'temperature':datas[0],

'pressure':datas[1],

'humidity':datas[2],

'gas':datas[3],

'updataTime':datas[4],

}

jsonData = json.dumps(content)

return HttpResponse(jsonData)

这时前端的页面如下所示:

这里虽然是前端页面,但其实不是给用户去看的,这个页面是供Wio Terminal做请求数据用的

2. 用正则表达式整理串口传回的数据

在前面我们留了一个getDatas()的方法没有讲到,原来的getDatas()方法只是单纯地获取数据而已,并没有对数据进行处理:

def getDatas():

serialPort = "COM10" # 串口

baudRate = 9600 # 波特率

ser = serial.Serial(serialPort, baudRate, timeout=0.5)

# print("参数设置：串口=%s ，波特率=%d" % (serialPort, baudRate))

while True:

str = ser.readline().decode('utf-8')

if str.strip()!='':

print(str)

updata_time = datetime.datetime.now().strftime('%F %T')

print(updata_time)

return str,updata_time

这里的改进是通过正则表达式把数据提取出来:

import re

import serial

import datetime

def getDatas():

serialPort = "COM10" # 串口

baudRate = 9600 # 波特率

ser = serial.Serial(serialPort, baudRate, timeout=0.5)

# print("参数设置：串口=%s ，波特率=%d" % (serialPort, baudRate))

while True:

lists = []

strs = ser.readline().decode('utf-8')

if strs.strip()!='':

print(strs)

str = re.finditer(r"(\d+).(\d+)",strs)

for item in str:

# print(item.group())

lists.append(float(item.group()))

updata_time = datetime.datetime.now().strftime('%F %T')

# print(updata_time)

lists.append(updata_time)

print(lists)

return lists

其实就是提取数据,把字符串里的有效信息提取出来,先存到一个列表里:

简单讲讲我这里用到的正则表达式:

re.finditer(r"(\d+).(\d+)",strs)

可以看到,想要提取的有效数据是带小数点后两位的数, \d 表示匹配任意数字，等价于0-9,但是小数点不是数字 ,所以不会被匹配,因此正则表达式可以写成: “(\d+).(\d+)”

3. 使用Wio Terminal做HTTP请求并展示数据

前两个部分是这一部分的基础,这一部分主要是Arduino的知识

我在做的时候,主要考虑3点:

连接WIFI并做HTTP请求

我拿到的Wio Terminal是样品,在使用无线连接前要在Wio Terminal上更新Wireless Core Realtek RTL8720的最新固件,大家拿到手里的应该都是已经刷好了的。如果在上传程序后,串口出现如下输出:

这时可尝试重新flash,具体方法请参考官方文档:

https://wiki.seeedstudio.com/Wio-Terminal-Network-Overview/

这一步解决以后,连接WIFI应该不成问题,看官方文档就能轻松解决,我这里讲一些比较特殊的部分。官方文档给了一个HTTPS的请求demo:

因为我现在只是在局域网内共享数据,因此用HTTP请求就行了。这里需要用到一些网络协议的知识,可以把HTTPS协议理解为HTTP协议的升级，就是在HTTP的基础上增加了数据加密,这个S即SSL。

有了这一基础就好办了,我们只需要在官方给的示例程序上稍作修改即可,先看看HTTPS请求:

#include

const char* ssid = "yourNetworkName"; // your network SSID

const char* password = "yourNetworkPassword"; // your network password

const char* server = "www.example.com"; // Server URL

const char* test_root_ca = \

"-----BEGIN CERTIFICATE-----\n"

"MIIDrzCCApegAwIBAgIQCDvgVpBCRrGhdWrJWZHHSjANBgkqhkiG9w0BAQUFADBh\n"

"MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3\n"

"d3cuZGlnaWNlcnQuY29tMSAwHgYDVQQDExdEaWdpQ2VydCBHbG9iYWwgUm9vdCBD\n"

"QTAeFw0wNjExMTAwMDAwMDBaFw0zMTExMTAwMDAwMDBaMGExCzAJBgNVBAYTAlVT\n"

"MRUwEwYDVQQKEwxEaWdpQ2VydCBJbmMxGTAXBgNVBAsTEHd3dy5kaWdpY2VydC5j\n"

"b20xIDAeBgNVBAMTF0RpZ2lDZXJ0IEdsb2JhbCBSb290IENBMIIBIjANBgkqhkiG\n"

"9w0BAQEFAAOCAQ8AMIIBCgKCAQEA4jvhEXLeqKTTo1eqUKKPC3eQyaKl7hLOllsB\n"

"CSDMAZOnTjC3U/dDxGkAV53ijSLdhwZAAIEJzs4bg7/fzTtxRuLWZscFs3YnFo97\n"

"nh6Vfe63SKMI2tavegw5BmV/Sl0fvBf4q77uKNd0f3p4mVmFaG5cIzJLv07A6Fpt\n"

"43C/dxC//AH2hdmoRBBYMql1GNXRor5H4idq9Joz+EkIYIvUX7Q6hL+hqkpMfT7P\n"

"T19sdl6gSzeRntwi5m3OFBqOasv+zbMUZBfHWymeMr/y7vrTC0LUq7dBMtoM1O/4\n"

"gdW7jVg/tRvoSSiicNoxBN33shbyTApOB6jtSj1etX+jkMOvJwIDAQABo2MwYTAO\n"

"BgNVHQ8BAf8EBAMCAYYwDwYDVR0TAQH/BAUwAwEB/zAdBgNVHQ4EFgQUA95QNVbR\n"

"TLtm8KPiGxvDl7I90VUwHwYDVR0jBBgwFoAUA95QNVbRTLtm8KPiGxvDl7I90VUw\n"

"DQYJKoZIhvcNAQEFBQADggEBAMucN6pIExIK+t1EnE9SsPTfrgT1eXkIoyQY/Esr\n"

"hMAtudXH/vTBH1jLuG2cenTnmCmrEbXjcKChzUyImZOMkXDiqw8cvpOp/2PV5Adg\n"

"06O/nVsJ8dWO41P0jmP6P6fbtGbfYmbW0W5BjfIttep3Sp+dWOIrWcBAI+0tKIJF\n"

"PnlUkiaY4IBIqDfv8NZ5YBberOgOzW6sRBc4L0na4UU+Krk2U886UAb3LujEV0ls\n"

"YSEY1QSteDwsOoBrp+uvFRTp2InBuThs4pFsiv9kuXclVzDAGySj4dzp30d8tbQk\n"

"CAUw7C29C79Fv1C5qfPrmAESrciIxpg0X40KPMbp1ZWVbd4=\n"

"-----END CERTIFICATE-----\n";

// You can use x.509 client certificates if you want

//const char* test_client_key = ""; //to verify the client

//const char* test_client_cert = ""; //to verify the client

WiFiClientSecure client;

void setup() {

//Initialize serial and wait for port to open:

Serial.begin(115200);

while(!Serial); // Wait for Serial to be ready

delay(1000);

Serial.print("Attempting to connect to SSID: ");

Serial.println(ssid);

WiFi.begin(ssid, password);

// attempt to connect to Wifi network:

while (WiFi.status() != WL_CONNECTED) {

Serial.print(".");

// wait 1 second for re-trying

delay(1000);

}

Serial.print("Connected to ");

Serial.println(ssid);

client.setCACert(test_root_ca);

//client.setCertificate(test_client_key); // for client verification

//client.setPrivateKey(test_client_cert); // for client verification

Serial.println("\nStarting connection to server...");

if (!client.connect(server, 443)) {

Serial.println("Connection failed!");

} else {

Serial.println("Connected to server!");

// Make a HTTPS request:

client.println("GET https://www.example.com HTTP/1.0");

client.println("Host: www.example.com");

client.println("Connection: close");

client.println();

while (client.connected()) {

String line = client.readStringUntil('\n');

if (line == "\r") {

Serial.println("headers received");

break;

}

}

// if there are incoming bytes available

// from the server, read them and print them:

while (client.available()) {

char c = client.read();

if (c == '\n') {

Serial.write('\r');

}

Serial.write(c);

}

client.stop();

}

}

void loop() {

// do nothing

}

WiFiClientSecure这个类是用来做HTTPS请求的,用setCACert(test_root_ca)进行认证

做HTTP请求时改成WiFiClient即可,并且不需要认证,这时我们就可以把很多代码都删掉了:

#include

const char* ssid = "yourNetworkName"; // your network SSID

const char* password = "yourNetworkPassword"; // your network password

const char* server = "Server URL"; // Server URL

WiFiClient client;

void setup() {

//Initialize serial and wait for port to open:

Serial.begin(115200);

while(!Serial); // Wait for Serial to be ready

delay(1000);

Serial.print("Attempting to connect to SSID: ");

Serial.println(ssid);

WiFi.begin(ssid, password);

// attempt to connect to Wifi network:

while (WiFi.status() != WL_CONNECTED) {

Serial.print(".");

// wait 1 second for re-trying

delay(1000);

}

Serial.print("Connected to ");

Serial.println(ssid);

Serial.println("\nStarting connection to server...");

if (!client.connect(server, 9000)) {

Serial.println("Connection failed!");

} else {

Serial.println("Connected to server!");

// Make a HTTP request:

String postRequest =(String)("GET ") + "/ HTTP/1.1\r\n" + "Connection: close\r\n\r\n";

Serial.println(postRequest);

client.print(postRequest);

while (client.connected()) {

String line = client.readStringUntil('\n');

if (line == "\r") {

Serial.println("headers received");

break;

}

}

// if there are incoming bytes available

// from the server, read them and print them:

while (client.available()) {

char c = client.read();

if (c == '\n') {

Serial.write('\r');

}

Serial.write(c);

}

client.stop();

}

}

void loop() {

// do nothing

}

这里需要注意的是client.connect(server, 9000),9000是我的端口,这里要选择正确的端口,否则是不能请求成功的;另外,我把PC端当作服务器,所以Server URL就是我的IP地址。

发送HTTP请求,最重要的是这部分:

// Make a HTTP request:

String postRequest =(String)("GET ") + "/ HTTP/1.1\r\n" + "Connection: close\r\n\r\n";

Serial.println(postRequest);

client.print(postRequest);

如果请求成功,终端会给出提示:

这个请求怎么写呢?这里其实有个好方法,想用浏览器访问,然后回终端看浏览器是怎么请求的,我们再照猫画虎即可。

获取数据并在LCD屏上显示

读取数据主要用到ArduinoJson这个库:

//ArduinoJson to parse data, plesae check ArduinoJson for more info

const size_t capacity = JSON_OBJECT_SIZE(5) + 100;

DynamicJsonDocument doc(capacity);

deserializeJson(doc, data);

float temperature = doc["temperature"];

float pressure = doc["pressure"];

float humidity = doc["humidity"];

float gas = doc["gas"];

String updataTime = doc["updataTime"];

把五个数据都读取出来,显示就很简单了。因为Wio Terminal的屏幕很小,所以我分了两页存放,原理都是相同的:

// -----------------LCD---------------------

tft.setFreeFont(FF17);

tft.setTextColor(tft.color565(224,225,232));

tft.drawString("Current Data At Home",20,10);

tft.fillRoundRect(10, 45, 300, 55, 5, tft.color565(40,40,86));

tft.fillRoundRect(10, 105, 300, 55, 5, tft.color565(40,40,86));

tft.fillRoundRect(10, 165, 300, 55, 5, tft.color565(40,40,86));

tft.setFreeFont(FM9);

tft.drawString("temperature:", 75, 50);

tft.drawString("pressure:",75, 110);

tft.drawString("humidity:",75, 170);

tft.setFreeFont(FMB12);

tft.setTextColor(TFT_RED);

tft.drawFloat(temperature,2 , 140, 75);

tft.setTextColor(tft.color565(224,225,232));

tft.drawFloat(pressure,2 , 140, 135);

tft.setTextColor(TFT_GREEN);

tft.drawFloat(humidity,2 , 140, 195);

tft.drawString("℃", 210, 75);

tft.drawString("KPa",210, 135);

tft.drawString("%",210, 195);

文字的摆放位置我是慢慢试出来的,这里要有耐心:

通过待机来省电

当然,在实际应用上,如果一直亮着屏幕,是很浪费电的,因此我结合加速度传感器,设置了一个待机状态,晃动Wio Terminal时才亮屏。

这块其实也很好做,在loop()里做就好了:

void loop()

{

float x_raw = lis.getAccelerationX();

float y_raw = lis.getAccelerationY();

float z_raw = lis.getAccelerationZ();

if (abs(accelerator_readings[0] - x_raw) >= 0.1 && abs(accelerator_readings[1] - y_raw) >= 0.1 && abs(accelerator_readings[2] - z_raw) >= 0.1){

// Turning on the LCD backlight

digitalWrite(LCD_BACKLIGHT, HIGH);

getFirstData();

delay(3000);

getLastData();

delay(3000);

}

else {

// Turning off the LCD backlight

digitalWrite(LCD_BACKLIGHT, LOW);

delay(500);

}

for (uint8_t i = 0; i<3; i++){

accelerator_readings[i] = 0.0; //this is used to remove the first read variable

}

accelerator_readings[0] = x_raw; //store x-axis readings

accelerator_readings[1] = y_raw; //store y-axis readings

accelerator_readings[2] = z_raw; //store z-axis readings

}

Wio Terminal自带三个加速度传感器,效果还是很理想的。

完整的代码

#include

#include

#include"LIS3DHTR.h"

#include"Free_Fonts.h"

#include"TFT_eSPI.h"

TFT_eSPI tft;

LIS3DHTR lis;

WiFiClient client;

const char* ssid = "zh213";

const char* password = "zh213wei";

const char* server = "192.168.1.102"; // Server URL

String data;

float accelerator_readings[3];

void setup() {

//Initialize serial and wait for port to open:

Serial.begin(115200);

delay(100);

pinMode(WIO_5S_PRESS, INPUT_PULLUP);

lis.begin(Wire1);

lis.setOutputDataRate(LIS3DHTR_DATARATE_25HZ);

lis.setFullScaleRange(LIS3DHTR_RANGE_2G);

float x_raw = lis.getAccelerationX();

float y_raw = lis.getAccelerationY();

float z_raw = lis.getAccelerationZ();

accelerator_readings[0] = x_raw; //store x-axis readings

accelerator_readings[1] = y_raw; //store y-axis readings

accelerator_readings[2] = z_raw; //store z-axis readings

Serial.print("Attempting to connect to SSID: ");

Serial.println(ssid);

WiFi.begin(ssid, password);

tft.begin();

tft.setRotation(3);

tft.fillScreen(TFT_BLACK);

tft.setFreeFont(FMB12);

tft.setCursor((320 - tft.textWidth("Connecting to Wi-Fi.."))/2, 120);

tft.print("Connecting to Wi-Fi..");

// attempt to connect to Wifi network:

while (WiFi.status() != WL_CONNECTED) {

Serial.print(".");

// wait 1 second for re-trying

delay(1000);

}

Serial.print("Connected to ");

Serial.println(ssid);

tft.fillScreen(TFT_BLACK);

tft.setCursor((320 - tft.textWidth("Connected!"))/2, 120);

tft.print("Connected!");

getFirstData();

}

void loop()

{

float x_raw = lis.getAccelerationX();

float y_raw = lis.getAccelerationY();

float z_raw = lis.getAccelerationZ();

if (abs(accelerator_readings[0] - x_raw) >= 0.1 && abs(accelerator_readings[1] - y_raw) >= 0.1 && abs(accelerator_readings[2] - z_raw) >= 0.1){

// Turning on the LCD backlight

digitalWrite(LCD_BACKLIGHT, HIGH);

getFirstData();

delay(3000);

getLastData();

delay(3000);

}

else {

// Turning off the LCD backlight

digitalWrite(LCD_BACKLIGHT, LOW);

delay(500);

}

for (uint8_t i = 0; i<3; i++){

accelerator_readings[i] = 0.0; //this is used to remove the first read variable

}

accelerator_readings[0] = x_raw; //store x-axis readings

accelerator_readings[1] = y_raw; //store y-axis readings

accelerator_readings[2] = z_raw; //store z-axis readings

}

void getFirstData() {

Serial.println("\nStarting connection to server...");

if (!client.connect(server, 9000)) {

Serial.println("Connection failed!");

tft.fillScreen(TFT_BLACK);

tft.setCursor((320 - tft.textWidth("Connection failed!"))/2, 120);

tft.print("Connection failed!");

} else {

Serial.println("Connected to server!");

// Make a HTTP request:

String postRequest =(String)("GET ") + "/ HTTP/1.1\r\n" + "Connection: close\r\n\r\n";

Serial.println(postRequest);

client.print(postRequest);

while (client.connected()) {

String line = client.readStringUntil('\n');

if (line == "\r") {

Serial.println("headers received");

break;

}

}

while(client.available())

{

String line = client.readStringUntil('\r');

data = line;

}

Serial.println(data);

client.stop();

Serial.println("closing connection");

}

//ArduinoJson to parse data, plesae check ArduinoJson for more info

const size_t capacity = JSON_OBJECT_SIZE(5) + 100;

DynamicJsonDocument doc(capacity);

deserializeJson(doc, data);

float temperature = doc["temperature"];

float pressure = doc["pressure"];

float humidity = doc["humidity"];

// -----------------LCD---------------------

tft.setFreeFont(FF17);

tft.setTextColor(tft.color565(224,225,232));

tft.drawString("Current Data At Home",20,10);

tft.fillRoundRect(10, 45, 300, 55, 5, tft.color565(40,40,86));

tft.fillRoundRect(10, 105, 300, 55, 5, tft.color565(40,40,86));

tft.fillRoundRect(10, 165, 300, 55, 5, tft.color565(40,40,86));

tft.setFreeFont(FM9);

tft.drawString("temperature:", 75, 50);

tft.drawString("pressure:",75, 110);

tft.drawString("humidity:",75, 170);

tft.setFreeFont(FMB12);

tft.setTextColor(TFT_RED);

tft.drawFloat(temperature,2 , 140, 75);

tft.setTextColor(tft.color565(224,225,232));

tft.drawFloat(pressure,2 , 140, 135);

tft.setTextColor(TFT_GREEN);

tft.drawFloat(humidity,2 , 140, 195);

tft.drawString("℃", 210, 75);

tft.drawString("KPa",210, 135);

tft.drawString("%",210, 195);

}

void getLastData() {

Serial.println("\nStarting connection to server...");

if (!client.connect(server, 9000)) {

Serial.println("Connection failed!");

tft.fillScreen(TFT_BLACK);

tft.setCursor((320 - tft.textWidth("Connection failed!"))/2, 120);

tft.print("Connection failed!");

} else {

Serial.println("Connected to server!");

// Make a HTTP request:

String postRequest =(String)("GET ") + "/ HTTP/1.1\r\n" + "Connection: close\r\n\r\n";

Serial.println(postRequest);

client.print(postRequest);

while (client.connected()) {

String line = client.readStringUntil('\n');

if (line == "\r") {

Serial.println("headers received");

break;

}

}

while(client.available())

{

String line = client.readStringUntil('\r');

data = line;

}

Serial.println(data);

client.stop();

Serial.println("closing connection");

}

//ArduinoJson to parse data, plesae check ArduinoJson for more info

const size_t capacity = JSON_OBJECT_SIZE(5) + 100;

DynamicJsonDocument doc(capacity);

deserializeJson(doc, data);

float humidity = doc["humidity"];

float gas = doc["gas"];

String updataTime = doc["updataTime"];

// -----------------LCD---------------------

tft.setFreeFont(FF17);

tft.setTextColor(tft.color565(224,225,232));

tft.drawString("Current Data At Home",20,10);

tft.fillRoundRect(10, 45, 300, 55, 5, tft.color565(40,40,86));

tft.fillRoundRect(10, 105, 300, 55, 5, tft.color565(40,40,86));

tft.fillRoundRect(10, 165, 300, 55, 5, tft.color565(40,40,86));

tft.setFreeFont(FM9);

tft.drawString("humidity:", 75, 50);

tft.drawString("gas:",75, 110);

tft.drawString("updataTime:",75, 170);

tft.setFreeFont(FMB12);

tft.setTextColor(TFT_RED);

tft.drawFloat(humidity,2 , 140, 75);

tft.setTextColor(tft.color565(224,225,232));

tft.drawFloat(gas,2 , 140, 135);

tft.setTextColor(TFT_GREEN);

tft.drawString(updataTime , 30, 195);

tft.drawString("%", 210, 75);

tft.drawString("Kohms",210, 135);

}

用一个视频展示一下效果:

简易智能家居中控系统(获取传感器实时数据)