How to use irrecord with 2ms timing instead of the default 5ms?

问题

I'm trying to teach lirc on my Raspberry Pi the remote-codes for my heat pump - a Mitsubishi Electric MSZ-GE60VA (remote is SG10A 1833)

I run irrecord as follows:

sudo /etc/init.d/lirc stop
irrecord -d /dev/lirc0 heatpump

I get the usual cruft about pushing buttons, etc, and duly do so.

After several dots (not always the same number), irrecord bails with the following error message:

irrecord: could not find gap.
irrecord: gap not found, can't continue

Now, I've found elsewhere that the sample rate might be wrong, and to look at the waveform using xmode2 - which I've done. I'm pretty sure I'd have more luck if I could get irrecord to sample faster, as xmode2 can.

Any ideas? (NB: I've run with the force option too, and no difference)

Here are my results using xmode2 - you can see the 5ms sample can't really make heads or tails of the signal, but the 2ms sample can.

5ms sample http://jnawk.net.nz/5ms.png 5ms sample (default)

2ms sample http://jnawk.net.nz/2ms.png 2ms sample

回答1:

First,try to use

irrecord -f -d /dev/lirc0 ~/lirc.conf

-f will force the raw mode. If you're lucky that will generate the config file or at list the gap.

Otherwise, launch the command below and ctrl^c to stop escape / stop recording.

mode2 -m -d /dev/lirc0 > ~/lirc.conf

the -m option should generate formated raws. remove the first value which is the delay before you pressed the remote button.

if you don't use the -m option you can do it with VI.

vim ~/lirc.conf
:%s/^.\{5}
:%s!^!    !
:%s/\n/

complete the ~/lirc.conf file to obtain something like :

begin remote

   name  MY_REMOTE
   flags RAW_CODES
   eps            30
   aeps          100

   frequency    38000
# note ensure the modulation frequency above correctly matches your remote, default is set to 38kHz
# you can also try other common frequencies (36000,40000,56000) if you are unsure

       begin raw_codes

           name MY_TEST
...<<PUT THE RAW CODE HERE >>...  

    end raw_codes
end remote

No TAB, only spaces in the file.

Make a backup of the original lircd.conf file

sudo mv /etc/lirc/lircd.conf /etc/lirc/lircd_original.conf

Copy over your new configuration file

sudo cp ~/lircd.conf /etc/lirc/lircd.conf

Start up lirc again

sudo /etc/init.d/lirc start

and try it

irsend SEND_ONCE MY_REMOTE MY_TEST

check with your phone camera the led is lighting.

This works for some people...

回答2:

LIRC actually samples as fast as 13 microseconds in raspberry pi which is the speed infrared lights pulse for IR signals (38kHZ), the timing you specify in xmode2 is just used in order to plot the image, each 2 ms it draws either a pulse or space on the graph.

The problem probably is in LIRC not detecting your remote IR code, have you tried running irrecord with the -f option? to force raw mode instead?

If this does not work you can use mode2 to actually try building your raw code manually and create the code like so: pulse time, space time, pulse time, space time and so on, expressed in microseconds.

From your graph it would be something like 6000 4000 1000 2000 1000 and so on...

Option 2- If you can find the pronto remote codes for your heat pump online then you can also convert them to lirc using pronto2lirc http://www.lirc.org/html/pronto2lirc.html

来源：https://stackoverflow.com/questions/22652156/how-to-use-irrecord-with-2ms-timing-instead-of-the-default-5ms

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raspberry-pi

lirc