I wrote earlier about how to use an IR remote on Raspbian Jessie.
It turns out several things have changed under Raspbian Stretch.
Update, August 2019:
Apparently these updated instructions don't work any more either. What apparently works now:
In /boot/config.txt, add:
In /etc/lirc/lirc_options.conf, add:
driver=default device = /dev/lirc0
/etc/modules and /etc/lirc/hardware.conf/ don't need to be changed. Thanks to Sublim21 on #raspberrypi for the tip.
Here's the older procedure and discussion.
Here's the abbreviated procedure for Stretch:
$ sudo apt-get install lirc
Enable the LIRC Overlay
Eedit /boot/config.txt as root, look for this line and uncomment it:
# Uncomment this to enable the lirc-rpi module dtoverlay=lirc-rpiOr if you prefer to use a pin other than 18, change the pin assignment like this:
# Uncomment this to enable the lirc-rpi module dtoverlay=lirc-rpi,gpio_in_pin=25,gpio_out_pin=17
See /boot/overlays/README for more information on overlays.
Fix the LIRC Options
Edit /etc/lirc/lirc_options.conf, comment out the existing driver and device lines, and add:
driver = default device = /dev/lirc0
Reboot and stop the daemon
Reboot the Pi.
Now a bunch of LIRC daemons will be running. You don't want them while you're configuring, and if you're eventually going to be reading button presses from Python, you don't want them at all.
Disable them temporarily with
sudo systemctl stop lircdwhich seems to be shorthand for
sudo systemctl stop lircd.socket sudo systemctl stop lircd.service
Be sure to check with
ps aux | grep lirc to make sure you've
turned them off.
If you want to disable them permanently,
sudo systemctl disable lircd.socket lircd.service lircd-setup.service lircd-uinput.service lircmd.serviceI got that list from:
systemctl list-unit-files | grep lirc
But you need them if you want to read from the /var/run/lirc/lircd socket.
Use mode2 to verify it sees the buttonsWith the daemons not running, a program called mode2 can verify that your device's buttons are being seen at all. I have no idea why it's named that, or what Mode 1 is.
mode2 -d /dev/lirc0
You should see lots of output. If you don't, double-check your wiring and everything else you've done up to now.
Set up an lircd.conf
Here's where it gets difficult. On Jessie, you could run
irrecord -d /dev/lirc0 ~/lircd.conf
as described in my
However, that doesn't work on stretch. There's apparently a
bug in the
irrecord in stretch that makes it generate a file that doesn't work.
If you try it and it doesn't work, run
tail -f /var/log/messages | grep lirc
and you may see Info: Cannot configure the rc device for /dev/lirc0
and when you press buttons you'll see Notice: repeat code without
last_code received but you won't get any keys.
If you have a working lirc setup from a Jessie machine, try it first. If it doesn't work, there's a script you can try that converts older lirc conf files to a newer format. The safest way to try it is to copy (with cp -a) the whole /etc/lirc directory to a local directory and run:
/usr/share/lirc/lirc-old2new your-local-copyOr if you feel brave, back up /etc/lirc and run sudo /usr/share/lirc/lirc-old2new with no arguments. Either way, you should get an lirc.conf that has a chance of working with stretch.
If you don't have a working Jessie config, you're in trouble. You might be able to edit the one from irrecord to make it work. Here's the first part of my working Jessie lircd.conf:
begin remote name /home/pi/lircd.conf bits 16 flags SPACE_ENC|CONST_LENGTH eps 30 aeps 100 header 9117 4494 one 569 1703 zero 569 568 ptrail 575 repeat 9110 2225 pre_data_bits 16 pre_data 0xFD gap 108337 toggle_bit_mask 0x0 begin codes KEY_POWER 0x00FF KEY_VOLUMEUP 0x807F KEY_STOP 0x40BF KEY_BACK 0x20DF KEY_PLAYPAUSE 0xA05F KEY_FORWARD 0x609F KEY_DOWN 0x10EFand here's the corresponding part of the nonworking one generated on Stretch:
begin remote name DingMai bits 32 flags SPACE_ENC|CONST_LENGTH eps 30 aeps 100 header 9117 4494 one 569 1703 zero 569 568 ptrail 575 repeat 9110 2225 gap 108337 toggle_bit_mask 0x0 frequency 38000 begin codes KEY_POWER 0x00FD00FF 0xBED8F1BC KEY_VOLUMEUP 0x00FD807F 0xBED8F1BC KEY_STOP 0x00FD40BF 0xBED8F1BC KEY_BACK 0x00FD20DF 0xBED8F1BC KEY_PLAYPAUSE 0x00FDA05F 0xBED8F1BC KEY_FORWARD 0x00FD609F 0xBED8F1BC KEY_DOWN 0x00FD10EF 0xBED8F1BC
It looks like setting bits to 16 and then using the second quartet from each key might work. So try that if you're stuck.
Once you get irw working, you're home free. The Python modules probably still won't do anything useful, but you can use my pyirw.py script as a model for a simple way to read keys from the lirc daemon.
In case you hit problems beyond what I saw, I found this discussion useful, which links to a complete GitHub gist of instructions for setting up lirc on Stretch. Those instructions have a couple of extra steps involving module loading that it turned out I didn't need, and on the other hand it doesn't address the problems I saw with irrecord. It looks like lirc configuration is a black art, not a science. See what works for you. Good luck!
[ 12:00 Nov 26, 2017 More hardware | permalink to this entry | comments ]