Hey OF folks, I picked up one of these very reasonably priced Planar 22" touch screens the other week.
The specifications indicated that it was only supported on Windows 7, but since it uses HID to communicate touch events, I thought I’d at least try to get it to talk to OSX.
I used some example code from Apple.com to figure out what channels the touch screen used for communicating events and so far I’ve been able to recognize X and Y coordinates and attribute those back to a finger ID, which is great.
The real problem comes with identifying touch up and down events and attributing them to the correct finger ID. What I’m noticing is that the incorrect finger IDs are being communicated. Here’s an example of what’s being output with 2 fingers pressing down and then lifting up. FYI, I’m printing out the hex value is the HID “usage” value, finger id, button value:
Finger #1 down:
0x47 1 1
Finger #2 down:
0x47 2 1
Finger #2 up:
0x47 2 0
Finger #1 up:
0x47 2 0
As you can see, the HID manager isn’t indicating that finger #1 is lifting. Do I have a doozie of a display or is it typical to have to do error checking when writing drivers for touch screens?
I’d be happy to share code if anybody has a Planar screen to test with. My next test is to plug this screen into a Windows machine and see if it displays the same unusual behaviors … just need to find a Windows machine.
Thanks++ for any advice!!