[izzy4505]

I'm trying to interface the IBM ThinkPad's accelerometer chip into a VB app. After much googling, it seems that there is this sensor.dll that handles everything. I've been marginally successful at using it so far, and I was wondering if I could get some help. I've used DLLs in apps before, but with documentation, and since there is none on this one, it's been a challenge for me. Here's the details.....

I came across this page: http://www.stanford.edu/~bsuter/thinkpad-accelerometer/

This guy has some code up (http://www.stanford.edu/~bsuter/thin...ter/ApsDemo.cs) written for .NET that calls ShockproofGetAccelerometerData() in the DLL. I'd like to use that function in my app. So I have the following code in a module:

Private Declare Function ShockproofGetAccelerometerData Lib "sensor.dll" (ByRef AccelData As Long) As Long

Public Function GetAccelData(ByRef x As Long, ByRef y As Long) As Long
Dim data As Long

''''Debug.Print "spgad: " & ShockproofGetAccelerometerData(data)
ShockproofGetAccelerometerData data
Debug.Print "data: " & data

End Function

When this runs, VB keeps saying "Bad DLL calling convention." A minute ago, I was able to get it to put some values in data which I'm assuming were pointers to a structure.

Any ideas on how I should get started with this? Thanks.

[izzy4505]

I am able to call another method in this DLL like this....

Private Declare Sub ShockproofGetShockStatus Lib "sensor.dll" (ByRef lStatus As Long)


Dim Status As Long
ShockproofGetShockStatus Status
Debug.Print Status

Not sure if that sheds any light on the problem or not, but this function works fine.

[cenit33]

Try this:

You are missing AccelData structure.

Private Type AccelData
    status As Long
    x As Integer
    y As Integer
End Type

You should declare the process like this

Private Declare Sub ShockproofGetAccelerometerData Lib "sensor.dll" (ByRef data As AccelData)

You must reserv memory for the structure and put values to it

Public Function GetAccelData(ByVal x As Integer, ByVal y As Integer) As Long
	Dim data As AccelData
	
	data.x = x
	data.y = y
	''''Debug.Print "spgad: " & ShockproofGetAccelerometerData(data)
	ShockproofGetAccelerometerData data
	Debug.Print "data: " & data.status

End Function

[izzy4505]

Woot, I was able to get the x, y, and status values. However it still pops up and says "Bad DLL calling convention...". It's weird, because the first time I run the code (being called from a form... code is in a module), it prints values and then pops the error. All later attempts (even upon running again!) it pops the error first and shows no values. Code I'm testing with:

Public Function GetAccelData() As Long
Dim data As AccelData

ShockproofGetAccelerometerData data

Debug.Print data.status
Debug.Print data.x
Debug.Print data.y

End Function

I am using your function declaration and user type.

[izzy4505]

Still stumped on this one.... I can't seem to get rid of the Bad DLL calling convention. A friend of mine suggested that maybe I couldn't use the DLL because of a way it was compiled?

[cenit33]

Try this

Private Declare Sub ShockproofGetAccelerometerData Lib "sensor.dll" _
    (ByRef data As Any)

ShockproofGetAccelerometerData ByVal data

or this

Private Declare Sub ShockproofGetAccelerometerData Lib "sensor.dll" _
    (ByVal data As Long)

ShockproofGetAccelerometerData VarPtr(data)

or this

Private Declare Sub ShockproofGetAccelerometerData Lib "sensor.dll" _
    (ByVal data As Long)

ShockproofGetAccelerometerData ByVal VarPtr(data)

[izzy4505]

No luck. The first code example you gave just crashes VB. The last two left data equal to empty.

[Cerian Knight]

Perhaps this will explain the problem (and provide a solution if you have the required resources): http://support.microsoft.com/kb/153586

[izzy4505]

I don't have the src to the DLL, so I am unable to change the calling method. However, I stumbled across some code which may solve this problem:
http://www.pscode.com/vb/scripts/Sho...xtCodeId=49776

So far, VB has been crashing when I've tried applying the method to sensor.dll, but I'm going to keep trying.

[Cerian Knight]

That might be made to work. You don't need the dll source code to implement Microsoft's solution...just the ability to write and compile something similar to their 'wrapper' example.