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发表于: 2019-8-16 21:27:29 | 显示全部楼层

如今，由于物联网系统的使用越来越多，了解物联网设备的运行和实施是非常重要的。在本篇文章中，我们将使用Arduino制作指纹考勤设备，除了将日志信息和工作时间存储在存储卡上之外，一旦连接到Internet，就将这些信息上传到Thingspeak平台上。您可以从面板以各种格式（如CSV）下载此信息。

什么是Thingspeak？

Iot（物联网）是一个平台，其中有许多东西连接到互联网，与个人和其他设备交互，并且通常将数据上传到云计算以进行分析。

Thingspeak是一个物联网平台，可让您在云计算中显示和收集实时数据。

与Thingspeak连接并上传数据

按照以下步骤启动Thingspeak连接：

步骤1）进入Thingspeak.com网站，然后创建一个帐户。

步骤2）激活帐户后登录，然后单击“My Channel”部分中的“New Channel”。

步骤3）在打开的新窗口中，在面板写一个名称，如果有必要，写下描述。通过分配名称来确定所需的字段数。其余部分是可选的。完成信息后保存面板。

步骤4）现在转到面板中的API Keys。

步骤5）您需要Channel ID和Write API Key来传输数据，因此请将其写下来。

步骤6）下载Thingspeak库并将其添加到Arduino IDE。Thingspeak库

步骤7）转到Arduino IDE。从示例部分打开WriteMultipleFiels，然后输入SSID、Password、Channel ID和Write API Key值。

/*
WriteMultipleFields
Description: Writes values to fields 1,2,3,4 and status in a single Thingspeak update every 20 seconds.
Hardware: ESP8266 based boards
!!! IMPORTANT - Modify the secrets.h file for this project with your network connection and Thingspeak channel details. !!!
Note:
- Requires ESP8266WiFi library and ESP8622 board add-on. See https://github.com/esp8266/Arduino for details.
- Select the target hardware from the Tools->Board menu
- This example is written for a network using WPA encryption. For WEP or WPA, change the WiFi.begin() call accordingly.
Thingspeak ( https://www.Thingspeak.com ) is an analytic IoT platform service that allows you to aggregate, visualize, and
analyze live data streams in the cloud. Visit https://www.Thingspeak.com to sign up for a free account and create a channel.
Documentation for the Thingspeak Communication Library for Arduino is in the README.md folder where the library was installed.
See https://www.mathworks.com/help/Thingspeak/index.html for the full Thingspeak documentation.
For licensing information, see the accompanying license file.
Copyright 2018, The MathWorks, Inc.
*/
#include "Thingspeak.h"
#include "secrets.h"
#include <ESP8266WiFi.h>
char ssid[] = SECRET_SSID; // your network SSID (name)
char pass[] = SECRET_PASS; // your network password
int keyIndex = 0; // your network key Index number (needed only for WEP)
WiFiClient client;
unsigned long myChannelNumber = SECRET_CH_ID;
const char * myWriteAPIKey = SECRET_WRITE_APIKEY;
// Initialize our values
int number1 = 0;
int number2 = random(0,100);
int number3 = random(0,100);
int number4 = random(0,100);
String myStatus = "";
void setup() {
Serial.begin(115200); // Initialize serial
WiFi.mode(WIFI_STA);
Thingspeak.begin(client); // Initialize Thingspeak
}
void loop() {
// Connect or reconnect to WiFi
if(WiFi.status() != WL_CONNECTED){
Serial.print("Attempting to connect to SSID: ");
Serial.println(SECRET_SSID);
while(WiFi.status() != WL_CONNECTED){
WiFi.begin(ssid, pass); // Connect to WPA/WPA2 network. Change this line if using open or WEP network
Serial.print(".");
delay(5000);
}
Serial.println("\nConnected.");
}
// set the fields with the values
Thingspeak.setField(1, number1);
Thingspeak.setField(2, number2);
Thingspeak.setField(3, number3);
Thingspeak.setField(4, number4);
// figure out the status message
if(number1 > number2){
myStatus = String("field1 is greater than field2");
}
else if(number1 < number2){
myStatus = String("field1 is less than field2");
}
else{
myStatus = String("field1 equals field2");
}
// set the status
Thingspeak.setStatus(myStatus);
// write to the Thingspeak channel
int x = Thingspeak.writeFields(myChannelNumber, myWriteAPIKey);
if(x == 200){
Serial.println("Channel update successful.");
}
else{
Serial.println("Problem updating channel. HTTP error code " + String(x));
}
// change the values
number1++;
if(number1 > 99){
number1 = 0;
}
number2 = random(0,100);
number3 = random(0,100);
number4 = random(0,100);
delay(20000); // Wait 20 seconds to update the channel again
}

复制代码

上传代码后，您将看到在面板的第1到4栏中上传的一些随机数字。在考勤系统中使用相同的结构代码来上载数据。

注意：每次在Thingspeak面板上上传数据之间至少等待15秒。

所需的材料

● Arduino Mega 2560 R3开发板

● R301T指纹传感器

● Micro SD TF卡适配器模块

● DS3231 I2C RTC模块

● 3.5“TFT彩色显示屏模块

● NodeMCU ESP8266 ESP-12E模块

● 公对母跳线

● Arduino IDE

使用指纹传感器和Arduino创建考勤系统

在该系统中，通过指纹登记到达和离开后，他的日期、姓名、到达时间、出发时间和工作时间等信息将存储在SD卡上。然后，此信息将在您指定的时间发送到Thingspeak。在没有Internet连接的情况下，未分发的数据将被存储，并在连接到Internet后立即转发到Thingspeak。由于信息存储在微控制器的EEPROM中，因此在断电时不会丢失。

电路连接

连接好所有模块后，将LCD扩展板插到Arduino开发板上。

代码

本文使用的代码需要以下库：

● Adafruit-Fingerprint-Sensor-Library

● Adafruit-GFX-Library

● MCUFRIEND_kbv

● RTClib

现在下载以下代码并将其上传到Arduino。此代码是为使用默认姓名的11人编写的，但您可以更改它们并将其从默认模式中删除。要注册新名称，只需将设备连接到计算机，然后按键进入注册模式，然后打开串行监视器并按照串行监视器上显示的注册过程进行操作。

从这里下载代码： Electropeak_Attendance_Code.zip (10.04 KB, 下载次数: 10)

Nodemcu执行在该系统中上传信息的任务。它从Arduino通过串口获取上传信息，并返回上传到Arduino的状态。在Nodemcu上上传以下代码。

#include "Thingspeak.h"
#include ESP8266WiFi.h>
char ssid[] = "YOUR SSID";
char pass[] = "SSID PASSWORD";
WiFiClient client;
unsigned long myChannelNumber = YOUR CHANNEL ID;
const char * myWriteAPIKey = "YOUR CHANNEL WRITE API KEY";
String Final = "";
String Date = "";
String Enter = "";
String Exit = "";
String Name = "";
String WT = "";
void String_Analyze(String input) {
int index1, index2, index3, index4;
index1 = input.indexOf('*', 0);
index2 = input.indexOf('*', index1 + 1);
index3 = input.indexOf('*', index2 + 1);
index4 = input.lastIndexOf('*');
Name = input;
Date = input;
Enter = input;
Exit = input;
WT = input;
Name.remove(index1);
Date.remove(index2);
Date.remove(0, index1 + 1);
Enter.remove(index3);
Enter.remove(0, index2 + 1);
Exit.remove(index4);
Exit.remove(0, index3 + 1);
WT.remove(0, index4 + 1);
}
void Get_String()
{
while (Serial.available()) {
Final = Serial.readString(); // read the incoming data as string
//Serial.println(Final);
}
}
void setup() {
Serial.begin(9600);
WiFi.mode(WIFI_STA);
Thingspeak.begin(client);
pinMode(LED_BUILTIN, OUTPUT);
digitalWrite(LED_BUILTIN, HIGH);
}
void loop() {
if (WiFi.status() != WL_CONNECTED) {
//Serial.print("Attempting to connect to SSID: ");
// Serial.println(ssid);
while (WiFi.status() != WL_CONNECTED) {
WiFi.begin(ssid, pass); // Connect to WPA/WPA2 network. Change this line if using open or WEP network
Serial.print("0");
delay(5000);
}
}
digitalWrite(LED_BUILTIN, LOW);
//Serial.println("\nConnected.");
Get_String();
String_Analyze(Final);
if (!Final.equals(""))
{
Thingspeak.setField(1, Date);
Thingspeak.setField(2, Name);
Thingspeak.setField(3, Enter);
Thingspeak.setField(4, Exit);
Thingspeak.setField(5, WT);
int x = Thingspeak.writeFields(myChannelNumber, myWriteAPIKey);
if (x == 200) {
delay(100);
Serial.print("1");
}
else {
delay(100);
Serial.print("0");
}
delay(17000);
Final = "";
}