| Re: reading from HID keyboard [message #180513 is a reply to message #180512] |
Sat, 23 February 2013 00:21  |
Ben Barker
Messages: 5
Registered: October 2011
Karma:
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Junior Member |
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On Friday, 22 February 2013 22:29:01 UTC, b...@bbarker.co.uk wrote:
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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.*
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> Ah - a useful little program fro the repositories call "evtest" has helped sort things out.
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> It seems that the data consists of a series of bytes, and for every key press/ character generated there are 8 bytes produced
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> Event: time 1361571412.662329, type 4 (EV_MSC), code 4 (MSC_SCAN), value 70027
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> Event: time 1361571412.662343, type 1 (EV_KEY), code 11 (KEY_0), value 1
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> Interspersed with
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> Event: time 1361571412.688401, -------------- SYN_REPORT ------------
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> It should be fairly easy to decode now :-)
This was also of much use:
http://stackoverflow.com/questions/5060710/format-of-dev-input-event
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