Button Map for the Samsung Q1-Ultra UMPC.

I’m working on a home automation project that involves amongst other things creating a software application that operates on Windows XP Tablet Edition running on a touchscreen-enabled Samsung Q1-Ultra Ultra Mobile Personal Computer (or UMPC).

One of the requirements of this application is that the UMPC will operate in a kiosk mode – okay simple enough, [perhaps I’ll post some information on accomplishing this by trapping certain key combinations and using the Windows Group Policy Editor if anyone is interested] but for this article the question is, “How do I disable some of the hardware buttons on the computer?”

We still want some of the hardware buttons to be available to the user.  Buttons such as “Vol-“, “Vol+”, as well as the traditional keyboard characters will be very useful, so we don’t want to disable them.  Other buttons will come in quite handy for purposes other than their intended uses, for example the arrow up and arrow down buttons on the user pad to the right will provide the user with handy Volume Up and Volume Down buttons (the Vol- and Vol+ buttons are used to control the volume locally on the UMPC where as these arrow up and arrow down buttons will send a control code to the AMX brain that will in-turn adjust the actual source volume for the various routed zones.

The first step of this task after determining the list of which hardware buttons we need to control or disable, is to identify how the system addresses these hardware keys.  I wrote a simple application that hooked into the low-level keyboard handler and trapped all values that came through.  From there I was able to create a table that shows for each hardware button what the BIOS key value is in both Hex and Decimal as well as the constants defined for those values in the Windows API WinUser.DLL library file and the .NET Windows.Forms.Key Keys enumerator.  Both of these are necessary because I wanted to trap some key codes in a dll and utilize some of the keys within the managed C# application.

Below I have provided the table showing the button mappings and the buttons’ relative positions on the UMPC.

Button	BIOS (Hex)	BIOS (Dec)	Windows (Hex)	WinUser DLL Constant	.Windows.Forms.Key
▲ Up	0x58	088	0xFF	VK_X	Keys.X
▼ Down	0x59	089	0xFF	VK_Y	Keys.Y
◄ Left	0x56	086	0xFF	VK_V	Keys.V
► Right	0x57	087	0xFF	VK_W	Keys.W
● Internet	0x32	050	0xAC	VK_2	Keys.D2
● Menu	0x54	084	0xFF	VK_T	Keys.T
● UDF	0x6E	110	0xFF	VK_DECIMAL	Keys.Decimal
● Q \ AV	0x74	116	0xFF	VK_F5	Keys.F5
● Shutter	0x64	100	0xFF	VK_NUMPAD4	Keys.NumPad4

One of the biggest concerns was the Internet button.  In a kiosk-type application that does not use the Internet, this button is a huge security hole in that people could launch Internet explorer and in the address bar use “File///…” and access anything within the UMPC.  It was a relief to me when I discovered that Samsung had used a standard keyboard key for the number 2 (above the Q and W on a QWERTY keyboard).  This meant there is a way to trap for that keystroke and prohibit it from launching the (in this case) Internet Explorer application.