从连接到树莓派的两个 RFID RC522 阅读器读取序列号、时间戳等数据

Question

有人可以帮我如何读取序列号，连接到Raspbery Pi的两个rfid阅读器的时间戳.python，c# .Net中有一些解决方案，但在javascript中没有。

我正在尝试与 Node Js 进行交互，但没有找到任何有用的资源来从两个 rfid 阅读器读取数据。

提前非常感谢

Answer 1

要从多个RFID阅读器读取数据，您可以使用以下内容：

1. 对于从节点读取数据：

有一些项目涉及从节点读取RFID标签，例如这里和这里。

此外，还有一些 npm 包，例如 rfidreader。

甚至还有专门用于RC522的，例如rc522-c7z

2. 对于多个阅读器：

每个读卡器都应由唯一的串行端口提供。这需要从步骤 1 传递到代码。

Answer 2

这是 Raspbbery Pi 上的 Windows 10 UWP 应用程序的示例。 您必须小心在 UWP ConSept 上使用异步编程。

using System;   
using System.Collections.ObjectModel;   
using System.Threading;   
using System.Threading.Tasks;   
using Windows.Devices.Enumeration;   
using Windows.Devices.SerialCommunication;   
using Windows.Storage.Streams;   
using Windows.UI.Xaml;   
using Windows.UI.Xaml.Controls;  
namespace Prova_comunicazione_seriale   
{   
public sealed partial class MainPage : Page   
{   
private SerialDevice serialPort = null;  
DataWriter dataWriteObject = null;   
DataReader dataReaderObject = null;  
private ObservableCollection<DeviceInformation> listOfDevices;   
private CancellationTokenSource ReadCancellationTokenSource;  
public MainPage()   
{   
InitializeComponent();  
btnAccendiled.IsEnabled = false;   
btnSpegniled.IsEnabled = false;   
listOfDevices = new ObservableCollection<DeviceInformation>();   
ListAvailablePorts();   
}  
private async void ListAvailablePorts()   
{   
try   
{   
string aqs = SerialDevice.GetDeviceSelector();   
var dis = await DeviceInformation.FindAllAsync(aqs);  
for (int i = 0; i < dis.Count; i++)   
{   
listOfDevices.Add(dis[i]);   
}  
lstSerialDevices.ItemsSource = listOfDevices;   
btnAccendiled.IsEnabled = true;   
btnSpegniled.IsEnabled = true;   
lstSerialDevices.SelectedIndex = -1;   
}   
catch (Exception ex)   
{   
tbkAllarmi.Text = ex.Message;   
}   
}  
private async void ButtonClick(object sender, RoutedEventArgs e)   
{   
var buttonClicked = sender as Button;  
switch(buttonClicked.Name)   
{   
case "btnSerialConnect":   
SerialPortConfiguration();   
break;  
case "btnSerialDisconnect":   
SerialPortDisconnect();   
break;  
case "btnAccendiled":   
if (serialPort != null)   
{   
dataWriteObject = new DataWriter(serialPort.OutputStream);   
await ManageLed("2");   
}  
if (dataWriteObject != null)   
{   
dataWriteObject.DetachStream();   
dataWriteObject = null;   
}  
break;  
case "btnSpegniled":   
if (serialPort != null)   
{   
dataWriteObject = new DataWriter(serialPort.OutputStream);   
await ManageLed("1");   
}  
if (dataWriteObject != null)   
{   
dataWriteObject.DetachStream();   
dataWriteObject = null;   
}  
break;  
case "btnPulse1000ms":   
if (serialPort != null)   
{   
dataWriteObject = new DataWriter(serialPort.OutputStream);   
await ManageLed("3");   
}  
if (dataWriteObject != null)   
{   
dataWriteObject.DetachStream();   
dataWriteObject = null;   
}  
break;  
case "btnPulse2000ms":   
if (serialPort != null)   
{   
dataWriteObject = new DataWriter(serialPort.OutputStream);   
await ManageLed("4");   
}  
if (dataWriteObject != null)   
{   
dataWriteObject.DetachStream();   
dataWriteObject = null;   
}  
break;   
}   
}  
private  async void SerialPortConfiguration()   
{   
var selection = lstSerialDevices.SelectedItems;  
if (selection.Count <= 0)   
{   
tbkAllarmi.Text = "Seleziona un oggetto per la connessione seriale!";   
return;   
}  
DeviceInformation entry = (DeviceInformation)selection[0];  
try   
{   
serialPort = await SerialDevice.FromIdAsync(entry.Id);   
serialPort.WriteTimeout = TimeSpan.FromMilliseconds(1000);   
serialPort.ReadTimeout = TimeSpan.FromMilliseconds(1000);   
serialPort.BaudRate = 9600;   
serialPort.Parity = SerialParity.None;   
serialPort.StopBits = SerialStopBitCount.One;   
serialPort.DataBits = 8;   
serialPort.Handshake = SerialHandshake.None;   
tbkAllarmi.Text = "Porta seriale correttamente configurata!";  
ReadCancellationTokenSource = new CancellationTokenSource();  
Listen();   
}  
catch (Exception ex)   
{   
tbkAllarmi.Text = ex.Message;   
btnAccendiled.IsEnabled = false;   
btnSpegniled.IsEnabled = false;   
}   
}  
private void SerialPortDisconnect()   
{   
try   
{   
CancelReadTask();   
CloseDevice();   
ListAvailablePorts();   
}   
catch (Exception ex)   
{   
tbkAllarmi.Text = ex.Message;   
}   
}  
private async Task ManageLed(string value)   
{   
var accendiLed = value;  
Task<UInt32> storeAsyncTask;  
if (accendiLed.Length != 0)   
{   
dataWriteObject.WriteString(accendiLed);                  
storeAsyncTask = dataWriteObject.StoreAsync().AsTask();  
UInt32 bytesWritten = await storeAsyncTask;   
if (bytesWritten > 0)   
{   
tbkAllarmi.Text = "Valore inviato correttamente";   
}   
}  
else   
{   
tbkAllarmi.Text = "Nessun valore inviato";   
}   
}  
private async void Listen()   
{   
try   
{   
if (serialPort != null)   
{   
dataReaderObject = new DataReader(serialPort.InputStream);  
while (true)   
{   
await ReadData(ReadCancellationTokenSource.Token);   
}   
}   
}  
catch (Exception ex)   
{   
tbkAllarmi.Text = ex.Message;  
if (ex.GetType().Name == "TaskCanceledException")   
{   
CloseDevice();   
}  
else   
{   
tbkAllarmi.Text = "Task annullato";   
}   
}  
finally   
{   
if (dataReaderObject != null)   
{   
dataReaderObject.DetachStream();   
dataReaderObject = null;   
}   
}   
}  
private async Task ReadData(CancellationToken cancellationToken)   
{   
Task<UInt32> loadAsyncTask;  
uint ReadBufferLength = 1024;  
cancellationToken.ThrowIfCancellationRequested();  
dataReaderObject.InputStreamOptions = InputStreamOptions.Partial;  
loadAsyncTask = dataReaderObject.LoadAsync(ReadBufferLength).AsTask(cancellationToken);  
UInt32 bytesRead = await loadAsyncTask;   
if (bytesRead > 0)   
{   
tbkStatusLed.Text = dataReaderObject.ReadString(bytesRead);                 
}   
}  
private void CancelReadTask()   
{   
if (ReadCancellationTokenSource != null)   
{   
if (!ReadCancellationTokenSource.IsCancellationRequested)   
{   
ReadCancellationTokenSource.Cancel();   
}   
}   
}  
private void CloseDevice()   
{   
if (serialPort != null)   
{   
serialPort.Dispose();   
}   
serialPort = null;  
btnAccendiled.IsEnabled = false;   
btnSpegniled.IsEnabled = false;   
listOfDevices.Clear();   
}   
}   
}
}