| Re: reading from HID keyboard [message #180512 is a reply to message #180509] |
Fri, 22 February 2013 22:29   |
Ben Barker
Messages: 5
Registered: October 2011
Karma:
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Junior Member |
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>> Hi,
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>> I have a device that appears to my machine as a HID keyboard (though actually it is an RFID reader)
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>> I can read from it locally in php by using fopen("php://stdin",r)
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>> The problem is if I shell into this machine via ssh, then stdin comes from the remote keyboard, not from the local HID device, and the above does not return any data.
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>> I can read from /dev/input/by-id/<my device>
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>> But this returns a very large number of bytes that it is not immediately obvious how to decode
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>> Can anyone suggest a way forward here?
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> It's hard to say without further information, but hazarding a guess,
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> you are reading raw keyboard scan codes in the latter case. If I was
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> in your situation, I'd look at the documentation for the device in
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> question, and take it from there. If your documentation is lacking,
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> try to look at the table of PS2 scan codes, and see if they match up
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> with your input.
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> http://www.computer-engineering.org/ps2keyboard/scancodes2.html
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> --
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> /Wegge
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> Leder efter redundant peering af dk.*,linux.debian.*
Ah - a useful little program fro the repositories call "evtest" has helped sort things out.
It seems that the data consists of a series of bytes, and for every key press/ character generated there are 8 bytes produced
Event: time 1361571412.662329, type 4 (EV_MSC), code 4 (MSC_SCAN), value 70027
Event: time 1361571412.662343, type 1 (EV_KEY), code 11 (KEY_0), value 1
Interspersed with
Event: time 1361571412.688401, -------------- SYN_REPORT ------------
It should be fairly easy to decode now :-)
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