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Touchmaster - 01 October 2008 08:02 AM

Latitude XT is limited to pinch zoom meaning that ntrig limits even the sdk to only gesture type input like pinch=zoom. When I use this feature the ntrig program just says the user is pinching, so zoom.  This is highly limited or almost useless because it doesn’t center on my finger tips accurately. 

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this still doesn’t mean the digitizer is not sending multiple individual touch coordinates to the os, just that it is not implemented in their SDK. It is still worth trying to poll the n-trig HID, to see what it is sending…

ke10 - 30 September 2008 09:14 AM

Daniel D - 30 September 2008 08:08 AM

You have to use RawInput API (http://msdn.microsoft.com/en-us/library/ms645536(VS.85).aspx)

great, can someone here use this to make a small debugging app to see what data we get from the latitude xt’s duosense digitizer?

It seems odd to me that there wouldn’t be some freeware available for reading the rawinput from a selected device.... But I can’t find any online...

try to google “usb sniffer”

For anyone needing info on raw input api.  here is the link: http://msdn.microsoft.com/en-us/library/ms645536.aspx

thanks Daniel for the name, i used a usb sniffer a while back for a mouse project but i just couldn’t remember what they are called. tks. but i did get it to spit out what is sent to the driver but i was doing it in during a presentation so i was paying full attention, im gonna look into it some more later today or on the weekend. the program i used is Device Monitoring Studio its a trial but it gets the job done for now:

http://downloads.zdnet.com/abstract.aspx?docid=306912

The Dell Latitude XT uses n-Trig’s technology which is “Capacitive Touch”.  Yes, they can detect more than 1 point… ...but not more than 3 due to occlusion.  Don’t let marketing “hype” get your hopes up.  I’ve been fortunate enough to test n-Trig’s stuff from the beginning and it’s definitely NOT multitouch in the sense that we know (all finger tips).  I wouldn’t waste your money on it if you want true multitouch because this doesn’t have it and will never have it.  Same goes for the HP TouchSmart PC.  Capacitive Touch.  Nothing more than an over marketed POS machine.

uhmmm actually the HP touchsmart 2 is not capacitive… but resistive. The first touchsmart, was optical, (had 2 optical sensors on the top of the screen), and thius was also single touch…

Capacitive is good: the iphone has a capacitive touch screen. The N-Trig does allow for multit touch. Look at the DELL and N-Trig videos online, (see youtube). the demonstrations clearly show people using the latitude XT (or other duosense screen) to, for example, draw with five fingers at once, or play “air hockey” with two players… (4 fingers)

whether the current firmware sends the tracking information to the OS is another question....

Interesting.

If the HP Touchsmart is resistive, that’s rather unfortunate since resistive solutions wear over time.

Sorry, apparently the new touchsmart also has an optical sensing method… not resistive. my mistake…

Did someone manage to poll the HID data from the latitude’s n-trig digitizer? I’d love to have a solid confirmation: does it or does it not send distinct touch coordinates to the os?

thanks!

not yet, i managed to get information from the HID but still not sure exactly what its sending,
ill post once i get more info

Hi iamakila,

thanks for trying this.
could you post the raw dat you’re getting so we could take a look at it?

i hope their are people still working on this, but i did manage to get some raw data, it is sending coordinates and it basically runs through every point so if you had 2 fingers it would give the coordinate for finger 1, then 2, then back to 1 (even if they are moving). im still trying to find out how it differentiates between the fingers. but the good news is that it is definitely sending coordinates, the x axis is from 0-9600 and the y axis is from 0 7200, more accuracy then we will really need. their are 2 other coordinates, and 3 other values that im not sure about, i think 1 of the 5 give the finger/object #, well, just wanted to post this so that people dont think the XT --> full fledged mulit-touch project is dead. ill try to post more but im in midterm week soooo, yahhhhh....lol

anybody else have an XT that is willing to help with the tests would be greatly appreciated,

Lamakila (with an L! lol)
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just got this so i thought i should post it too:

i just understood what the “In range” means, that basically tells if it is touching the screen, so when you let go, it changes back to 0 and sends the last coordinates for your finger.
im still not too sure what tip switch, Unknown, and the two Unknown coordinates.
the two unknown coordinates might have something to do wiht pressure or the size of the blob/point/finger

here is one report:
005618: Report Arrived (UP), 14.10.2008 12:15:06.386 +0.007
Report Name:Touch Screen
In Range: 1
Tip Switch: 1
Unknown: 1
X[0..9600]/[0..9600]: 7383
Y[0..7200]/[0..7200]: 2938
Unknown[0..7200]/[0..7200]: 0
Unknown[0..7200]/[0..7200]: 0

Can it be that Unknown coordinates are from Pen? Pen can be “In range”, “Tip down”, “Side switch down”, “inverted”, “eraser down”.
Here are data structs from Wacom digitizer. It may have similarities with n-trig:

[Flags]
internal enum PenStatus : byte
{
PenTipDown = 0x01,
SideSwitchDown =0x02,
Inverted = 0x04,
EraserDown = 0x08,
Reserved = 0x18,
InRange = 0x20,
ControlData = 0x40,
Sync = 0x80
}

[StructLayout(LayoutKind.Sequential)]
internal struct PEN_DATA
{
public byte ReportID;
public PenStatus Status;
public ushort X;
public ushort Y;
public ushort Pressure;
public byte XTilt;
public byte YTilt;
public ushort Firmware;
public int Data;

public override string ToString()
{
return string.Format("Report ID: {0}, Status: {1}, X-Y: {2}x{3}, Pressure: {4}, Tilt X-Y: {5}x{6}, Firmware: {7}, Data: {8}”,
ReportID, Status, X, Y, Pressure, XTilt, YTilt, Firmware, Data);
}
}

Iamakilla, that is great!
what happens when you put 3 or 4 fingers down?

this could give more insight into what the other numbers mean…