You have to add a form to your worksheet and the write a macro that does the
function

I would start by going to fromat menu and selecting learn macro.  then
manually get the data from the twain device.   Then stop record the macro.

then test the macro and see if it works.

the next step is to add a button that automatically calls the macro.

1) go to view window - toolbars and select form Menu.
2) Select the control button and add it to your worksheet
3) right click the conjtrol button and select the macro you want to run
4) right click on the button and select edit text to change the text on the
button.

This brings up the dialog for the user to select from.

Const FromScannerorCamera As Long = 1764
Application.CommandBars.FindControl(, FromScannerorCamera).Execute

Not sure what you mean by "without installing activex", but if the button is
from the Controls Toolbox, make sure you set its .TakeFocusOnClick property
to False.

NickHK