[mythtv-users] Re: MythTV and Sky

mythtv guy mythtvguy at yahoo.co.uk
Mon Aug 1 18:53:11 UTC 2005

--- Allan Stirling <Dibblahmythml0015 at pendor.org>

> Date: Tue, 14 Jun 2005 21:40:34 +0100
> From: Allan Stirling <Dibblahmythml0015 at pendor.org>
> To: Discussion about mythtv
> <mythtv-users at mythtv.org>
> Subject: Re: [mythtv-users] Re: MythTV and Sky
> > Have a look at this.
> > 
> >
> > 
> > I've not tried it yet, but have got all the stuff
> and should get
> > around to it soon.
> It works well enough - However, there were still
> missed channel changes 
> for me. How this works is it allows LIRC to output
> the 32khz modulated 
> IR (Modulated in software), which is then modulated
> on top of a 433Mhz 
> (IIRC) carrier onto the input of the box.
> For me, I got ghetto on the Sky box. If you remove
> the front panel and 
> the PCB, you can see the IR receiver (silver box
> with black window). 
> Either remove the receiver or cut the track leading
> from it's output - 
> The 3 leads are 5v, Ground and output. I'm afraid
> the box is in the 
> attic - So I can't give the pinout.
> You can then attach the serial port to this input in
> the same fashion as 
> shown on the above site - Multiple signal diodes to
> drop the voltage.
> You then need to load the lirc-serial driver with
> the option:
> options box1xmit_serial softcarrier=0
> However, there's still a problem. The IR receiver in
> the Sky box is 
> active-high, if I remember correctly. This is
> opposite to most other IR 
> modules. This means that you have to record your own
> lircd.conf (Since 
> any recorded by anyone else will tend to be wrong) -
> Or, like I usually 
> do, you can cheat.
> Change the following functions in lirc_serial.c:
> static inline void on(void)
> {
>          soutp(UART_MCR,hardware[type].off);
> }
> static inline void off(void)
> {
>          soutp(UART_MCR,hardware[type].on);
> }
> But hey, that's just me. Noone else is this nuts.
> Just thought someone 
> might enjoy this tale of waaaay excessive hardware
> hacking.
> Cheers,
> Allan.
> _______________________________________________
> mythtv-users mailing list
> mythtv-users at mythtv.org


Your solution interests me as it is what I would have
liked to do in the first place.  You have inspired me
to try it myself - I am driving the serial port DTR
through a voltage divider into a CMOS inverter to give
me a 5v inverted signal which i can feed into the box
in place of the IR sensor signal.  In fact I am
AND'ing the two together so either the IR sensor or
the DTR signal can be used.

Trouble is it would appear as though the remote codes
in my lircd.conf file are no good for this approach.

The sky box certainly doesnt recognise commands sent
from the PC and when I monitor it on an oscillosope
the waveform seems to be every different to that seen
when I press the equivalent buttons on the remote.  Do
you have a copy of the lircd.conf file you used that
you could send me?

At first I missed off the lirc_serial options you
mentioned and I hoped that would be the problem but
even after adding them it still behaves the same way.

Do you have any other ideas why this wouldn't be
working.  Having got this close I would love to be
able to see it through now.

Thanks for any help you can give.

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