Windows CE Programming

Hello Readers

it has been a long time since my last post, I was a little bit busy.

This time I want to present some experimental code to visualize and analyze G-Sensor data. The goal was to achieve a shake detection algorithm. Unfortunately the device under test only provided 1 sample per second and that is not enough for a good shake detection. Beside that the code and classes developed may help you to find your way and they help you at last to determine the current orientation of the device.

left shows general information taken from vector, right shows a log with last vector data

[image SensorScan5_0102.gif]

[image SensorScan5_0304.gif]
left shows graphical of vector and force (length), right shows indicators for detected events

A g-sensor or accelerometer sensor normally gives you the x, y and z-values of a vector. A vector is an imaginary arrow with a direction and length starting from the three dimensional point 0,0,0. The vector direction points to the acceleration of the device. The normal acceleration on earth is 9,81m/s^2. If the device is on the desk, the y-acceleration is about minus 9.81m/s^2. The absolute value of the sensor may vary on the sensor and maybe defined as 1.0 for -9.81m/s^2 or -0.981. If you through the device up to the air, the x,y and z-values will reach 0,0,0 as if the device is weightless. Keep in mind that the acceleration towards the middle of the earth is always there and the device will come back to you.

Here is another visualization of the vector and a device (done with visual python, [Download not found]):

[image vectors.gif]

The device is facing upwards (see y arrow) with the top facing to you (the z arrow). The left side of the device is pointing to the right (the x arrow).

The light green/blue and the yellow arrows demonstrate two different vectors which show the direction (the xyz angles) and the force (the vector lengths) to the device.

Continue reading ‘Mobile Development – Shake that thing’ »

Hello

here is one other way to write a kios mode .NET application using a technique called SubClassing. The idea was born by a comment of redwolf2222 on this blog about how to Hide Start and Close buttons on Windows Mobile 6.5 devices. Redwolf2222 also provided a code snippet. Unfortunately it was incomplete and so I wrote my own class.

Disable clicks on Start and Close button

The demo project shows one dialog with two check boxes and you can easily test the function. If “StartButton Disabled” or “Close Button disabled” is checked, you cannot ‘click’ the corresponding button any more:

You still ‘click’ the buttons but the subclassed window will not ‘execute’ your click. The buttons are part of the toolbar32 window which is a child of the menu_worker window. So first we have to follow the window tree.

Find the right window

/// <summary>
/// SubClassing: Install the wndproc hook
/// </summary>
/// <returns></returns>
private bool hookWindow()
{
    //find taskbar
    IntPtr hWndTaskbar = FindWindow("HHTaskbar", IntPtr.Zero);
    if (hWndTaskbar == IntPtr.Zero)
        return false;
    //enable the taskbar, not realy necessary
    EnableWindow(hWndTaskbar, true);
    //already installed?
    if (oldWndProc == IntPtr.Zero)
    {
        //find the menu_worker window
        IntPtr hwndMenu_Worker = FindWindow("menu_worker", IntPtr.Zero);
        if (hwndMenu_Worker != IntPtr.Zero)
        {
            //get the child window which has the buttons on it
            IntPtr hwndToolbar = GetWindow(hwndMenu_Worker, GetWindow_Cmd.GW_CHILD);
            if (hwndToolbar != IntPtr.Zero)
            {
                _mHwnd = hwndToolbar;       //store to remember
                SubclassHWnd(hwndToolbar);  //subclass the wndproc
            }
        }
    }
    return true;
}

Subclassing

Now, as we have the window handle, the subclassing can be started:
Continue reading ‘Mobile Development: Disable Windows Mobile 6.5 Start and Close Button’ »

Hello

here is another kiosk mode library. It supports disabling clicks/taps on start menu icon and opening the Windows Mobile start menu using the win key (VKLWIN). Additionally there is a function to disable the whole StartMenu bar and one to make a window fullscreen without Done and Close button (uses SHFullScreen).

The functions are implemented in a DLL, so you can easily use them from C/C++, the dot net compact framework (CSharp or VB.NET), Java and so on.

Here is a list of the functions exported by the DLL:

void __stdcall LockStartMenu(); // this will install the hook (subclass the taskbar window)
void __stdcall UnlockStartMenu();   // this will unhook TaskbarWindowProc from taskbar
void __stdcall LockStartBar();  // this disables the whole taskbar
void __stdcall UnlockStartBar();    // this enables the taskbar window
bool __stdcall Lockdown(TCHAR*);    // this will make the application with the window title fullscreen etc
bool __stdcall Unlockdown();    // this will 'normalize' the fullscreen window

I have included a deno application in C and .NET

The left shows normal window ce window and the right the same window after pressing the [Lockdown window].

Continue reading ‘Mobile Development: Yet another kiosk mode library’ »

For an actual project I needed a tftp server service for a Windows 2003 server. I looked around in internet and only found tftp servers running in user space, no real windows service. So I searched for source code applications I could use and found tftpUtil at sourceforge.net (http://sourceforge.net/projects/tftputil/). Although the short description states it would implement a service, it does not in reality. But the tftpUtil class was more or less easy to use and so I started to write a service ‘wrapper’ around it.

        protected override void OnStart(string[] args)
        {
            AddLog("OnStart entered...");
            StartTFTPServer();
...
        }

Continue reading ‘Writing a tftp server windows service’ »