nice document about HID devices and an alternative

[Scott Cytacki]

I just stumbled on this discussion of HID usb devices:

http://www.libusb.org/wiki/FAQ#CanIcreateadriverlessdeviceusingHIDclass

It provides some info on why using HID devices is not necessary a good solution for driverless usb devices.  We also found this out because Chrome's USB support does not work with HID drivers:

https://code.google.com/p/chromium/issues/detail?id=148836

The libusb info does point to using an alternative approach for driverless devices: using standard windows drivers. I read up on this a bit and found this interesting document:

http://msdn.microsoft.com/en-us/library/windows/hardware/hh450799.aspx

If I'm reading that correctly it means that sensor vendors could use that WinUSB compatible device ID in their devices and then they would work without needing to install a driver. All of the sensor devices we currently work with don't require drivers on OS X.  This woud probably also mean the device could be made to work with Chrome's existing USB API. So they would also work with chrome books. 

However at the same time there is this library:

http://www.signal11.us/oss/hidapi/

Which exposes a cross platform api to HDI devices which doesn't require the removal and reattaching a kernel driver. And if you look at the comments on the chromium bug there are people interested adding this api to chromium.

I cc'd Mat at vernier because he was interested in connecting devices to Chrome Books.

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Scott Cytacki

The Concord Consortium

http://concord.org