[mythtv-users] LIRC: sending the same IR code multiple times (repeated, but not repeating) results in receiving device seeing only one instance

Gary Buhrmaster gary.buhrmaster at gmail.com
Sat Apr 14 01:20:32 UTC 2012


On Fri, Apr 13, 2012 at 12:06, Tom Metro <tmetro+mythtv-users at gmail.com> wrote:
...
> I'm using the IguanaWorks USB IR transceiver
> (http://iguanaworks.net/products/usb-ir-transceiver/) in a send-only
> application with lirc 0.8.6-0ubuntu3~ppa5~hardy1 and iguanair 1.0.1-1 on
> Ubuntu 8.04, with the lirc.conf shown here:
> http://lirc.sourceforge.net/remotes/motorola/DTA100
>
> if I run the command:
>
> % irsend SEND_ONCE MotorolaDTA100-PaceDC50X KEY_3 KEY_3 KEY_ENTER
>
> instead of the receiving device switching to ch 33, it goes to ch 3.

This is typical.  Most IR receivers have "de-bounce" protection
because either the remote or the user is likely to "bounce" a key.
As you suspect, there needs to be some "idle" time between
duplicate keys.

> An interesting observation: when I tried a 3-digit number, there was
> slight, but noticeable delay between the 1st and 2nd number, then the
> DTA immediately showed the call sign for the 2-digit station, as if the
> enter key had been sent, even though it hadn't.

The DTA has a timeout, which allows you to send one or two
keys, and wait (or hit enter) to tune.  Since the current channel
maps only allow 3 digits, once the DTA gets that third, it is
done, and tunes without the enter.

On the wiki there is a sample lirc tuning script which as
part of the examples has values for delays that seem to
work for iguanaIR and Pace DTAs (it also have a lot of
other features that may be overkill).

Gary


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