在树莓派3上使用红外遥控器控制libreELEC和Raspbian系统
使用红外接收头在树莓派上遥控libreELEC
1.修改config.txt文件：
默认只读模式，重新挂载为读写模式
文档地址：https://wiki.libreelec.tv/config.txt
mount -o remount,rw /flash
nano /flash/config.txt
mount -o remount,ro /flash
2.添加gpio-ir
Add the following line to /flash/config.txt (read Raspberry Pi Config.txt for detailed instructions):
dtoverlay=gpio-ir
Add the gpio_pin parameter if you used a custom GPIO (default is 18). eg:
dtoverlay=gpio-ir,gpio_pin=5
3.测试按键输出代码，建立keymaps
ir-keytable -t
Testing events. Please, press CTRL-C to abort.
293.356686: lirc protocol(nec): scancode = 0x46
293.406665: lirc protocol(nec): scancode = 0x46 repeat
293.636664: lirc protocol(nec): scancode = 0x46
293.690013: lirc protocol(nec): scancode = 0x46 repeat
294.560006: lirc protocol(nec): scancode = 0x15
294.613348: lirc protocol(nec): scancode = 0x15 repeat
294.879998: lirc protocol(nec): scancode = 0x15
295.180040: lirc protocol(nec): scancode = 0x15
295.436699: lirc protocol(nec): scancode = 0x15
295.786679: lirc protocol(nec): scancode = 0x15
295.836676: lirc protocol(nec): scancode = 0x15 repeat
296.059997: lirc protocol(nec): scancode = 0x15
296.556677: lirc protocol(nec): scancode = 0x44
297.140018: lirc protocol(nec): scancode = 0x44
根据编码在/storage/.config/rc_keymaps/下创建my_custom_remote
我的定义：注意nec是上面的协议，可再用ir-keytable -t -p nec进行测试
# table my_custom_remote, type: nec
0x46 KEY_UP
0x15 KEY_DOWN
0x44 KEY_LEFT
0x43 KEY_RIGHT
0x40 KEY_OK
0x7 KEY_BACK
0x9 KEY_MENU
4.停止服务：
systemctl stop kodi
systemctl stop eventlircd
5.载入新的keymaps：
ir-keytable -c -w /storage/.config/rc_keymaps/my_custom_remote
再进行测试
ir-keytable -t
如果能看到上面的按键显示输出，表明测试成功
6. 开启服务，进行测试
systemctl start kodi
systemctl start eventlircd
7.添加：/storage/.config/rc_maps.cfg文件
文档说明：When you’re finished with all buttons, save the keytable, stop ir-keytable -t with CTRL+C and then test if it works. If testing succeeds, make it permanent via a /storage/.config/rc_maps.cfg file like this:
* * my_custom_remote
总结：在4.19内核版本和前面4.14内核版本中lirc配置有所不同。
本文主要参考官方文档：
文档地址：Infrared Remotes
8.在树莓派Raspbian系统中使用方法：
注意：在4.19版本内核下，不要安装lirc软件，只安装ir-keytable.
- use dtoverlay=gpio-ir to activate the kernel drvier (make sure you DON’T use lirc_rpi)
- apt-get install v4l-utils ir-keytable to get ir-keytable
- if necessary change the IR remote settings (protocol, scancodes) via /etc/rc_maps.cfg and/or custom keymaps in /etc/rc_keymaps
- apt-get install inputlirc and configure it to translate the linux input events from the IR driver into lirc events - this is what kodi currently supports best
That’s about the same setup as we use in LibreELEC, only difference is that we use eventlircd instead of inputlirc (and, before you ask: no, eventlircd isn’t in debian and you also are better off with inputlirc)
You can stick to the guide in the LibreELEC wiki https://wiki.libreelec.tv/infrared_remotes - just keep in mind that the paths are a bit different than in Debian/Raspbian (/storage/.config instead of /etc, /flash instead of /boot)
参考：网址
不知道怎么默认启动通过/etc/rc_maps.cfg方式，直接把下面加入到rc.local中
sudo ir-keytable -c -w /etc/rc_keymaps/my_custom_remote.toml
my_custom_remote.toml：
[[protocols]]
name = "my_custom_remote"
protocol = "nec"
variant = "nec"
[protocols.scancodes]
#0x25 = "KEY_POWER"
#0x0a = "KEY_MUTE"
#0x01 = "KEY_1"
#0x02 = "KEY_2"
#0x03 = "KEY_3"
#0x04 = "KEY_4"
#0x05 = "KEY_5"
#0x06 = "KEY_6"
#0x07 = "KEY_7"
#0x08 = "KEY_8"
#0x09 = "KEY_9"
#0x00 = "KEY_0"
0x46 = "KEY_UP"
0x15 = "KEY_DOWN"
#0x12 = "KEY_VOLUMEUP"
#0x13 = "KEY_VOLUMEDOWN"
#0x1f = "KEY_RECORD"
#0x17 = "KEY_PLAY"
#0x16 = "KEY_PAUSE"
#0x0b = "KEY_STOP"
#0x27 = "KEY_FASTFORWARD"
#0x26 = "KEY_REWIND"
0x40 = "KEY_OK"
0x44 = "KEY_LEFT"
0x43 = "KEY_RIGHT"
0x07 = "KEY_BACK"
0x09 = "KEY_MENU"
#0x2b = "KEY_EPG"
#0x1e = "KEY_RED"