[GTALUG] Emulating a USB keyboard using ???

[William Park]

On Sat, Dec 05, 2015 at 11:39:01AM -0500, Lennart Sorensen wrote:
> On Sat, Dec 05, 2015 at 11:10:40AM -0500, William Park wrote:
> > Hi guys,
> > 
> > Do you know a way to emulate a USB keyboard using Raspberry Pi,
> > BeagleBone Black, ODROID, or some other embedded board?  That is, as far
> > as PC is concerned, it's receiving keypresses from some keyboard.
> > 
> > I know those boards have UART pins.  But, even if I connect the pins to
> > a serial-to-USB cable, the USB end of the cable will show up as serial
> > (/dev/ttyUSBx) and not as keyboard.  I have such a cable, and that's
> > what I see.
> 
> If it supports linux's USB gadget interface then you should be in luck:
> 
> https://www.kernel.org/doc/Documentation/usb/gadget_hid.txt

Thanks for the link.  It even has sample code for testing!  

> 
> Raspberry pie can NOT do it, since it has a permanent USB hub connected,
> and you can't have a hub connected to the port to use it in gadget mode
> (since gadget mode means being a USB client, not a host).
> 
> The BBB on the hand can do it.  I didn't check the others.

Both BeagleBone Black and ODROID-U3 have USB mini-B port, and do mention
USB "client mode" in their online specs.  So, I'm encouraged.
-- 
William