[mythtv-users] Controlling a satellite box from MythTV

Brian Wood beww at beww.org
Tue Feb 13 14:53:47 UTC 2007

On Feb 12, 2007, at 9:12 PM, Dewey Smolka wrote:

> So I bought the MyBlaster device, had it up and running within 15
> minutes of it arriving at my door, and haven't had to touch it or
> think about it since. It's been up and running for nearly a year, and
> I've had maybe five cases where it failed to properly change the
> channel (out of thousands of channel changes). Even when I managed to
> coax some output from my serial lirc blaster, the failure rate was
> significant enough to be worrying -- I estimated at the time that it
> failed 10 to 20 percent of the time, and that was when it was working.

At least part of the problem is that LIRC-driven "blasters" are  
pretty much "kludge" devices. They use the control signals of the  
RS-232C port in a totally non-standard way to drive an LED emitter,  
and depending on the precise characteristics of both the serial port  
and the LED can give somewhat variable results. Even at best the IR  
output is limited and thus so is the range, and the possibility of  
interference from outside light sources etc. is high.

The MyBlaster, OTOH, is driven by a serial port in its "normal"  
manner, using the data lines in a totally standard way. All the  
timings are generated  internally, and do not depend on software to  
generate them. Since the device has its own DC power supply the IR  
output is not dependent on the current available from control lines,  
it is fixed and high, so there is much less chance of unreliable  
operation or interference.

The LIRC blasters usually have to be within a foot or two of the IR  
receiver, while I have got reliable results from the MyBlaster from  
30 feet away in a sunlit room.

Neither solution is "right" or "wrong", they are just two different  
approaches and the best solution depends on what is best for you.

> As always YMMV, but the MyBlaster is $50 well spent.

I happen to agree, but that's speaking as someone who had the $50 in  
the first place, not everyone does :-)

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