[mythtv-users] New MythTV IR Hardware going Beta

Matthew Bodkin lists at innovationone.ca
Tue May 27 21:43:49 UTC 2008


On Tue, 2008-05-27 at 16:36 -0400, Peter A. Daly wrote:
> On Tue, May 27, 2008 at 10:58 AM, Matthew Bodkin <lists at innovationone.ca> wrote:
> >> Matthew,
> >>
> >> Does your device generate its own IR carrier frequency in hardware,
> >> or does it rely on LIRC to do it in software?
> 
> > The carriers are hardware generated.  The new one actually has 4
> > separate carrier generators (1 for each of the 4 transmitters) so
> > differently modulated devices can be controlled at the same time.
> 
> Because I'm fairly ignorant about IR/lirc, but curious...

Hi Pete, 

No problem!

> Why does this matter and how would this help me over an lirc generated
> carrier frequency?  (If I'm even using the correct terminology.)  Can
> you explain it in somewhat non-technical end user terms?

It's somewhat analogous to WinModems vs USRobotics back in the day -
"soft" modems vs "hardware"-implemented communications.  WinModems were
less/cheaper hardware, but required alot more CPU clocks to run; USR's
performed rock-solidly.  Same thing here. 

Outsourcing the signal generation (signal timing & carrier) to hardware
ensures it's 100% accurate every time.  Unlike modems, there's no
feedback to "retry" the command (you'll miss the recording or record the
wrong show).  Set-top boxes are the 'hardest' because they have a higher
carrier frequency (more cycles/millisecond=more sensitive to CPU delays)

If you have a system that works great with a serial blaster, then great;
serial reliability can depend on a bunch of hardware/software things.
Some people have no problems while some people think its their config
setup that's not right when they don't work.  The hardware-based stuff
consistently works.

> Why go with CommandIR over a serial ir blaster, other than the 3
> additional blasters?

- Reliability (see above)
- Consistency (see above)
- Actually, 4 CommandIRs can be used together for up to 16 'blasters'
- Configuring multiple blasters isn't as easy as just plugging them in
(multiple LIRC instances are a huge pain, impossible for newbies)
- Most people have a limit number of serial ports, sometimes none
- CommandIR combines the blaster(s) and a receiver, so again 1 LIRC
instance for everything.  Many USB receivers are tied to 1 remote too.
- You'd be surprised how many people like having a blue light to aim
remotes at for their SO or family
- And the new CommandIR2 stuff; programmable LEDs, parallel control,
future RF RX+TX, etc; if enough people are interested in remote-wake
from any remote, that might get into a future edition too.
- Commercial integrators like CommandIR too; selling a $600++ box
without supporting multiple-devices isn't competitive.

In my experience over the past few years, as more and more people get
their first Linux experience with a MythTV distro they want something
that will work reliably, doesn't require days/weekends to setup, and
that can grow with their system.  

So there's markets for both serial blasters and CommandIR for sure.
Ever tried 2+ WinModems in the same box? :)

Matthew
--
InnovationOne Applied Technology - CommandIR
www.commandir.com


> -Pete
> MythPVR.com




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