Tweaking the Logitech R400 presenter tool on Linux
==================================================

.. articleMetaData::
   :Where: London, UK
   :Date: 2013-01-09 09:21 Europe/London
   :Tags: blog, php, mongodb
   :Short: r400

**This article is outdated, please refer to a `new version`__.**

__ /logitech-r400-take2.html

**Updated on April 9th, 2013, after comments by Jim Diamond**

For Christmas I received a `Logitech R400`_ presenter tool as a replacement
for the `php|architect`_ one that has now fallen apart. However, to use it
together with my presentation system—pres2, about which I previously_ wrote—I
need it to provide left and right arrow keypresses. By default its *left* and
*right* buttons generate *Prior* and *Next* events in X.

It took me a while to get this to work, so in short, this is how I changed it.
First of all, I created the file ``/etc/udev/logitech-r400`` as root
with contents::

	0x70037 f5
	0x70029 f11
	0x7003E f11
	0x7004B left
	0x7004E right

.. image:: images/logitech-r400.png
   :align: left

This maps the two scan codes that the *Play* button (lower-left) both to *f11*,
the empty screen button to *f5* and the left and right buttons to the left
and right arrow keys. 

The first column represents the scancode, which I obtained by first looking up
with input event the device was tied to::

	stat -t /dev/input/by-id/usb-Logitech_USB_Receiver-event-kbd --printf "%N\n"

Which showed the following for me::

	‘/dev/input/by-id/usb-Logitech_USB_Receiver-event-kbd’ -> ‘../event16’

Then with ``event16`` I ran::

	/lib/udev/keymap -i input/event16

And pressed all four buttons (and the *Play* button twice). This then showed up
on the screen::

	scan code: 0x7004B   key code: pageup
	scan code: 0x7004E   key code: pagedown
	scan code: 0x7003E   key code: f5
	scan code: 0x70029   key code: esc
	scan code: 0x70037   key code: dot

After creating the file, to test things I ran::

	sudo /lib/udev/keymap input/event16 /etc/udev/logitech-r400

Which showed::

	Remapped scancode 0x70037 to 0x3f (prior: 0x34)
	Remapped scancode 0x70029 to 0x57 (prior: 0x01)
	Remapped scancode 0x7003e to 0x57 (prior: 0x3f)
	Remapped scancode 0x7004b to 0x69 (prior: 0x68)
	Remapped scancode 0x7004e to 0x6a (prior: 0x6d)

After this ran, the presenter tool now sends the key presses that I want. To
make this permanent, I added as root a new file
``/etc/udev/rules.d/logitech.rules``, with as contents::

	ENV{ID_VENDOR}=="Logitech*", ATTRS{idProduct}=="c52d", RUN+="keymap $name /etc/udev/logitech-r400"

The changes will now also persist after rebooting as well.

My first possibility to test the new tool will be at `PHP Benelux`_ where
I will be giving a MongoDB_ tutorial_ on January 25th. Tickets are still
available_.


.. _`Logitech R400`: http://www.amazon.co.uk/gp/product/B002L3TSLQ/ref=as_li_ss_tl?ie=UTF8&tag=derickrethans-21&linkCode=as2&camp=1634&creative=19450&creativeASIN=B002L3TSLQ
.. _`php|architect`: http://www.phparch.com/
.. _previously: /presentations.html
.. _`PHP Benelux`: http://conference.phpbenelux.eu/2013/
.. _tutorial: http://conference.phpbenelux.eu/2013/sessions/#mongodb-workshop
.. _MongoDB: http://mongodb.org
.. _available: http://myupcoming.com/en/event/35892/phpbenelux-conference-2013