From Arduino to C#: How to Read & Save to CSV(2025 Guide)

void setup() {
  Serial.begin(115200); //you can use any option available
}

void loop() {
  int sensorValue = analogRead(A0); // Read analog sensor
  Serial.println(sensorValue);  
   //in this code i am using this as a sample serial data
 Serial.print("RcvData koki-: 0, cmd:123, data 2343, 23344, 0,0,345,123,0,0,44,44,44,0,0,0,0,0 ");
 Serial.println("OyakiData : 3450.44, 20.41,0.00,0.00,0.00");
  delay(1000); // Wait 1 second
}

using System.IO.Ports;
using System.IO;

 private void InitializeSerialPort()
 {
     serialPort = new SerialPort
     {
         PortName = "COM9", // ⚠️ Adjust to your port
         BaudRate = 115200,
         Parity = Parity.None,
         DataBits = 8,
         StopBits = StopBits.One,
         Handshake = Handshake.None
     };
     serialPort.DataReceived += SerialPort_DataReceived;
 }
  private void InitializeTimer()
 {
     uiUpdateTimer = new Timer
     {
         Interval = 100 // ms
     };
     uiUpdateTimer.Tick += UiUpdateTimer_Tick;
     uiUpdateTimer.Start();
 }

  //connect
  private void button1_Click(object sender, EventArgs e)
  {
      try
      {
          if (!serialPort.IsOpen)
          {
              serialPort.Open();
              button1.BackColor = Color.Green;
              button3.BackColor = Color.Gray;
          }
          else
          {
              MessageBox.Show("シリアル通信されています.");
          }
      }
      catch (Exception ex)
      {
          MessageBox.Show("Error: " + ex.Message);
          button1.BackColor = Color.Red;
      }
  }
  //disconnect
   private void button3_Click(object sender, EventArgs e)
 {
     if (serialPort.IsOpen)
     {
         serialPort.Close();
         button1.BackColor = Color.Gray;
         button3.BackColor = Color.Red;
     }
 }

 private void SerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
 {
     try
     {
         string line = serialPort.ReadLine();
         serialQueue.Enqueue(line);
     }
     catch (Exception ex)
     {
         serialQueue.Enqueue("Read error: " + ex.Message);
     }
 }

 private void UiUpdateTimer_Tick(object sender, EventArgs e)
 {
     while (serialQueue.TryDequeue(out string data))
     {
         string cleaned = CleanReceivedData(data);

         if (!string.IsNullOrWhiteSpace(cleaned) && !cleaned.Trim().Equals("00") &&
             !cleaned.Trim().Equals("mode-0") && !cleaned.Trim().Equals("mode-1"))
         {
             AppendToRichTextBox(cleaned);
             UpdateDataGridView(cleaned);
         }
     }
 }

 private string CleanReceivedData(string input)
 {
     try
     {
         string cleaned = input.Replace("RcvData koki-: ", "")
                               .Replace("cmd:", "")
                               .Replace("data ", "");

         int oyakiIndex = cleaned.IndexOf("OyakiData : ");
         if (oyakiIndex < 0) return input;

         string firstPart = cleaned.Substring(0, oyakiIndex).Trim();
         string secondPart = cleaned.Substring(oyakiIndex + "OyakiData : ".Length).Trim();
         string result = $"{firstPart},{secondPart}";

         return Regex.Replace(result, @"\s*,\s*", ",");
     }
     catch
     {
         return input;
     }
 }

 private void UpdateDataGridView(string dataRow)
 {
     try
     {
         string[] values = dataRow.Split(',');

         if (values.Length == 23)
         {
             // Prepend serial number
             string[] newRow = new string[24];
             newRow[0] = serialNumber.ToString();
             for (int i = 0; i < 23; i++)
             {
                 newRow[i + 1] = values[i];
             }

             dataGridView1.Rows.Add(newRow);
             serialNumber++;

             dataGridView1.FirstDisplayedScrollingRowIndex = dataGridView1.RowCount - 1;
         }
         else
         {
             AppendToRichTextBox($"Invalid data length: {values.Length} (expected 23)");
         }
     }
     catch (Exception ex)
     {
         AppendToRichTextBox("Grid update error: " + ex.Message);
     }
 }
 

 private void button2_Click(object sender, EventArgs e)
 {
     try
     {
         using (SaveFileDialog saveFileDialog = new SaveFileDialog())
         {
             saveFileDialog.Filter = "CSV files (*.csv)|*.csv|All files (*.*)|*.*";// save the data to csv file
             saveFileDialog.FilterIndex = 1;
             saveFileDialog.RestoreDirectory = true;
             saveFileDialog.FileName = $"ArduinoData_{DateTime.Now:yyyyMMdd_HHmmss}.csv";

             if (saveFileDialog.ShowDialog() == DialogResult.OK)
             {
                 StringBuilder csvContent = new StringBuilder();
                 var headers = dataGridView1.Columns.Cast<DataGridViewColumn>().Select(c => c.HeaderText);
                 csvContent.AppendLine(string.Join(",", headers));

                 foreach (DataGridViewRow row in dataGridView1.Rows)
                 {
                     if (!row.IsNewRow)
                     {
                         var cells = row.Cells.Cast<DataGridViewCell>()
                                             .Select(cell => EscapeCsvValue(cell.Value?.ToString() ?? ""));
                         csvContent.AppendLine(string.Join(",", cells));
                     }
                 }

                 File.WriteAllText(saveFileDialog.FileName, csvContent.ToString());
                 MessageBox.Show($"Data saved successfully to:\n{saveFileDialog.FileName}",
                                 "Export Complete", MessageBoxButtons.OK, MessageBoxIcon.Information);
             }
         }
     }
     catch (Exception ex)
     {
         MessageBox.Show($"Error saving CSV file:\n{ex.Message}",
                         "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
     }
 }