SurfacePen

Use the Microsoft Surface BLE Pen to do something different than opening OneNote.

Intro

The purple Surface Pen button normally launches OneNote. I don't really use OneNote, but I find it interesting to control my tablet "remotely".

I used Microsoft SysInternal's Process Monitor to find out what actually happens when you press the pen's purple button.

How it works

It turns out that the Windows Registry key

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Authentication\LogonUI\CN

determines what will be executed. The default value is C:\Program Files\Microsoft Office 15\Root\Office15\ONENOTEM.EXE but you can change it to anything, e.g. launch the calculator (C:\Windows\System32\calc.exe)

The specified executable will always be passed an command line argument:

• Single press: /hardwareinvoke
• Double press: /screenclip
• Lockscreen press: /fromlockscreen

I proceeded to write a simple AutoHotkey script:

if 1 = /hardwareinvoke ; single button press
    Send {Right}
else if 1 = /screenclip ; double button press
    Send {Left}

and compiled it to pen.exe and updated the registry key to its path (C:\bin\pen.exe for me)

Files

pen.exe is the compiled version of pen.ahk

pen.reg contains a registry patch as per [KB310516]https://support.microsoft.com/en-us/kb/310516). It will change the value of the key given above to the value C:\bin\pen.exe.

reset.reg will reset that value to the default (C:\Program Files\Microsoft Office 15\Root\Office15\ONENOTEM.EXE)

Issues

The double press always dims the screen shortly and then takes a screenshot before executing the program. I couldn't figure out how to suppress that. Maybe someone has an idea?

Conclusion

Now I can use my Surface Pen to control presentations :)