main.frm

ecg source code in c++

    
    ' Open the audio input device - I removed the reference to sink as a callback
    '  that was in the original call
    ' WAVE_MAPPER means to open any device that can handle the type of audio
    ' (specified in WF) that we want, preferably the one set as your default.
    rc = waveInOpen(pDevHandle, WAVE_MAPPER, WF, 0, 0, CALLBACK_NULL)
        
    If (rc <> 0) Then   ' Now make sure that there are no errors
      waveInGetErrorText rc, msg, Len(msg)
      MsgBox msg
      Exit Sub
    End If

    ' pDevHandle now contains a pointer to reference further device calls
    ' (In other words, waveInOpen found a device for us to use, then gave
    '  us a pointer so we can keep using the device)
    ' Now we check to make sure it got a device

    If (pDevHandle = 0) And (rc = 0) Then
        MsgBox "Couldn't start capturing audio!", vbExclamation
        Exit Sub
    End If

' We have memory, we have an open wave device, now we assign it the buffer
' First, get the header ready - define it
    With pWaveHeader
'        .lpData = pWaveMem      'Points to where to save data
        .lpData = pData      'Points to where to save data
        .dwBufferLength = pcSamplesPerSecond * 2 * Buffer.Text  'Size of buffer in bytes
        .dwBytesRecorded = 0    'How much data is recorded so far
        .dwUser = 0             ' I don't know what goes here
        .dwFlags = 0
        .dwLoops = 0            ' Not used for input buffers
    End With
' Now we need to prepare the header with the function (the header is 32 bytes big)
    rc = waveInPrepareHeader(pDevHandle, pWaveHeader, Len(pWaveHeader))
' And assign the buffer to be filled
    rc = waveInAddBuffer(pDevHandle, pWaveHeader, Len(pWaveHeader))
' And now start filling the buffer
    rc = waveInStart(pDevHandle)

    'Set how often to update the graph
    Timer1.Interval = 50
    RateTimer.Interval = 3000


    ' Everything seems to have executed correctly, so change the caption
    Command1.Caption = "Stop Recording"
End Sub
Public Function getaddr(ByVal bla As Long) As Long
    getaddr = bla
End Function

Private Sub Stop_Recording()
    
    ' Close the waveout device
    rc = waveInReset(pDevHandle)
    rc = waveInClose(pDevHandle)
    
'I don't need to deallocate the memory because now I use the array
    ' De-allocate any memory used
'    rc = HeapDestroy(pWaveHeap)
'    pWaveHeap = 0

    Timer1.Interval = 0

End Sub


Private Sub Form_Unload(Cancel As Integer)
'Do these commands before exiting the program

    ' Make absolutely sure that I closed the device
    rc = waveInReset(pDevHandle)
    rc = waveInClose(pDevHandle)
    
    ' De-allocate any memory used (just for good housekeeping)
    'rc = HeapDestroy(pWaveHeap)
End Sub

Private Sub RateTimer_Timer()
    ' A pulse did not come in the expected range - reset the output to 0
    HeartRate.Text = 0
    Comment.Text = "You appear to be dead. Perhaps you should call 911"
End Sub

Private Sub Timer1_Timer()
    Update_Graph
End Sub

Function findY(ByVal index As Integer) As Long
    'Calculate the y-value (equals average of data through the point)
    Dim i As Long
    Dim startx As Long
    Dim endx As Long
    Static prevYneg As Boolean
    
    startx = Int(index / Picture1.ScaleWidth * pWaveHeader.dwBufferLength / 2)
    endx = Int((index + 1) / Picture1.ScaleWidth * pWaveHeader.dwBufferLength / 2)
    If endx > pcSamplesPerSecond * pcMaxSeconds Then endx = pcSamplesPerSecond * pcMaxSeconds
    
    findY = 0
    If (startx = endx) Then
        findY = data(startx)
    Else
        'findY = data(startx)
        For i = startx To endx
            findY = findY + data(i)
        Next i
        findY = findY / (startx - endx)
    End If
    findY = findY / 2 ^ 16 * Picture1.ScaleHeight
    If (prevYneg) Then
        If (findY > TriggerLevel.Text * Picture1.ScaleHeight / 2) Then
            edge_trigger (index)
            prevYneg = False
        End If
    ElseIf (findY < TriggerLevel.Text * Picture1.ScaleHeight / 2) Then
        prevYneg = True
    End If
    If (maxY < findY) Then maxY = findY
End Function

Function findTrigger()
    'Determine what level to set the trigger point to
    ' - evaluated by .5*peak output
    If (maxY > 5) Then
        TriggerLevel.Text = maxY / Picture1.ScaleHeight
    Else
        TriggerLevel.Text = 0.5
    End If
    maxY = 0
End Function

Function edge_trigger(ByVal index As Integer)
    'An edge trigger has occured, calculate the heart rate
    Static prevIndex As Integer
    If (index <> prevIndex) Then
        If (index > prevIndex) Then
            HeartRate.Text = Int(60 / Buffer * Picture1.ScaleWidth / (index - prevIndex) * 10) / 10
        Else
            HeartRate.Text = Int(60 / Buffer * Picture1.ScaleWidth / (index - prevIndex + Picture1.ScaleWidth) * 10) / 10
        End If
    End If
    'If HeartRate.Text < 40 Then
    '    HeartRate.Text = 10
    'End If
    prevIndex = index
    
    'Put some comments in the heart rate
    If HeartRate.Text > 300 Then
        Comment.Text = "Heart rate is high. Electrodes connected correctly?"
    ElseIf HeartRate.Text > 110 Then
        Comment.Text = "Work that body!"
        Beep
    ElseIf HeartRate.Text > 50 Then
        Comment.Text = "Dum de dum de do"
        Beep
    Else
        Comment.Text = "Yawn"
        Beep
    End If
    
    ' Assume a minimum heart rate of 20BPM and estimate when the worst case pulse should come
    RateTimer.Enabled = False
    RateTimer.Interval = 3000
    RateTimer.Enabled = True

End Function

Private Sub Update_Graph()
    'The timer has precidence over other processes, so when it goes
    ' off, the wave device stops writing to the data().  This means
    ' that if we read the data() now, it may be mixed with old data
    ' To solve this problem, I increased the delay to write the output
    ' In other words, say we just read in 1000 bytes making a total of 5000
    ' bytes read so far.  We won't update the bytes 4000 to 5000 on the
    ' plot, but will update bytes 3000 to 2000 (the previous chunk of data
    ' read in)
    Dim Point As Long   'The point to read the value
    Dim refreshLeft As Long   'The left point to refresh
    Dim refreshRight As Long     'The right point to refresh
    Dim numPoints As Long       'The number of points to graph
    Dim i As Long               'Some random variable
    Dim Yval(pcSamplesPerSecond * 2 * pcMaxSeconds + 1) As Long  'The Y-values
    Dim futureX As Integer      'What the X-coordinate is to refresh the data next time
    Dim mmdata As MMTIME        ' Used to find how much data we've read
    Static prevX As Long        ' The last X coordinate updated
    Static nowX As Long         ' The one before the last X coord updated - update prevX to nowX on plot
    
        ' First find out how much we've recorded
    mmdata.wType = TIME_BYTES
    rc = waveInGetPosition(pDevHandle, mmdata, Len(mmdata))
        'Text1.Text now has the byte to read from in data()
    Text1.Text = mmdata.dwData Mod pWaveHeader.dwBufferLength
    
        ' Then find out what the x-coord is for where we are
    futureX = Int(Text1.Text / (pWaveHeader.dwBufferLength) * Picture1.ScaleWidth)
        ' Calculate the data points and refresh the data for the previous data set
    If (prevX > nowX) Then        'We've wrapped around the screen
        For i = prevX To Picture1.ScaleWidth
            Yval(i) = findY(i)
        Next i
        For i = 0 To nowX
            Yval(i) = findY(i)
        Next i
    Else
        For i = prevX To nowX
            Yval(i) = findY(i)
        Next i
    End If
'Erase the parts that need to be refreshed and draw the new stuff (but the last
' data point may be bad, so don't draw that one)
    If (prevX > nowX) Then
        Picture1.Line (0, -Picture1.ScaleTop)-(nowX, Picture1.ScaleTop), Picture1.BackColor, B
        Picture1.Line (prevX + 1, -Picture1.ScaleTop)-(Picture1.ScaleWidth, Picture1.ScaleTop), Picture1.BackColor, B
        For i = 1 To nowX
            Picture1.Line ((i - 1), -Yval(i - 1))-((i), -Yval(i))
        Next i
        For i = prevX + 1 To Picture1.ScaleWidth
            Picture1.Line ((i - 1), -Yval(i - 1))-((i), -Yval(i))
        Next i
    Else
        Picture1.Line (prevX + 1, -Picture1.ScaleTop)-(nowX, Picture1.ScaleTop), Picture1.BackColor, B
        For i = prevX + 1 To nowX
            Picture1.Line ((i - 1), -Yval(i - 1))-((i), -Yval(i))
            'Picture1.Circle (i, Yval(i)), 1
        Next i
    End If
    
        'Now update the pointers so we can keep everything straight
    prevX = nowX
    'If prevX < 0 Then prevX = 0
    nowX = futureX

'If we've reached the end of the buffer, reset it (but we like the old data, so keep it there)
    If (pWaveHeader.dwFlags = WHDR_DONE) And (Command1.Caption = "Stop Recording") Then
        rc = waveInAddBuffer(pDevHandle, pWaveHeader, Len(pWaveHeader))
'        pWaveHeader.dwBytesRecorded = 0
        'Also, do some cleanup that needs to be done
        If (AutoTrigger.Value = 1) Then
            rc = findTrigger()
        End If
        Picture1.Line (0, -TriggerLevel.Text * Picture1.ScaleHeight / 2)-(Picture1.ScaleWidth, -TriggerLevel.Text * Picture1.ScaleHeight / 2), &HFFFFC0
    End If
    'Picture1.Line (0, 0)-(Picture1.ScaleWidth, Picture1.ScaleHeight)
End Sub