Author Topic: Why CEC Control Your TV Using Your RaspberryPi?  (Read 206 times)

totallymaxed

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Why CEC Control Your TV Using Your RaspberryPi?
« on: October 21, 2014, 05:03:44 pm »
One of the most important uses for HDMI CEC is in fact to wake your TV up from 'Standby'. Why? Well almost all TV's when placed into 'Standby' mode unfortunately also power down their network interface chip too, which means you can't use IP control to wake the TV up. However HDMI CEC is always waiting for commands, and is never powered down when your TV is in 'Standby' mode - unless you set your TV to power it off in 'Standby' that is.

This means therefore placing an HDMI CEC controller behind your TV's - even your brand new SmartTV's, is about the only solution to powering them up from 'Standby' under control of your system. In fact we have many installations that simply use our Dianemo Raspbmc-CEC software for Rpi even with a brand new SmartTV, which has in own built uPnP media playback capability, to just to wake the TV up from 'Standby'. Even systems that have traditional Media Managers driving their TV's can use our Dianemo Raspbmc-CEC software on Rpi to send on/off commands to their TV's.

Whether your planning to use your Rpi with Raspbmc-CEC firmware as a upnp media player and UI (ie a replacement for a Media Director) + CEC controller or purely as a CEC controller for your TV, you can use your Orbiters UI to send control commands to the Rpi to browse, select & stream media and also to power on/off your TV.

How many TV's support HDMI CEC control? In our experience if your TV has an HDMI port and was manufactured in the last 6 years it will almost certainly support CEC and specifically at least On/Off. So you may well have an older TV that has no RS232 or IP control capability but has an HDMI port - this almost certainly means HDMI CEC control is possible.

Find out more about Dianemo CEC Control for Rpi here; http://www.ellipticalcurve.com/dianemo-products-services/ and info about Dianemo Licensing offers here; http://forum.linuxmce.org/index.php?topic=8880.msg100221#msg100221

Whether you have a LinuxMCE or a Dianemo Installation if you have any comments or questions about CEC control, or anything related to it, please post them here in this thread. You can also email or PM me - see the footer below for details.

All the best

Andy
« Last Edit: October 23, 2014, 08:14:34 pm by totallymaxed »
Andy Herron,
Convergent Home Technologies Ltd

Read My Blog; http://ellipticalcurve.com

Contact me for Smart Home consulting advice here;
@herron on Twitter, inquiries@ellipticalcurve.com via email or PM me here.

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posde

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Re: Why CEC Control Your TV?
« Reply #1 on: October 22, 2014, 12:52:11 am »
or find one of the few display devices that is controllable via RS232 :)

totallymaxed

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Re: Why CEC Control Your TV?
« Reply #2 on: October 22, 2014, 01:57:33 am »
or find one of the few display devices that is controllable via RS232 :)

Yes if you have a TV with RS232 you could do that. But that's really only an option with an older TV.
« Last Edit: October 22, 2014, 04:14:49 pm by totallymaxed »
Andy Herron,
Convergent Home Technologies Ltd

Read My Blog; http://ellipticalcurve.com

Contact me for Smart Home consulting advice here;
@herron on Twitter, inquiries@ellipticalcurve.com via email or PM me here.

Get a Dianemo License: http://forum.linuxmce.org/index.php?topic=8880.msg100221#msg100221
Follow us on Facebook: https://www.facebook.com/pages/Dianemo-Home-Automation/226019387454465

Sales & Info:
http://www.dianemo.co.uk

jamo

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Re: Why CEC Control Your TV?
« Reply #3 on: October 22, 2014, 08:09:04 am »
So, Andrew, if users just have the CEC from the RPI to power on the TV, does that mean they occupy one of the HDMI inputs on the TV just to do that? I'm presuming the RPI CEC can't "pass through" the signal from another device?

Pretty poor show that TVs with IP control don't implement WOL. So much for SMART.

posde

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Re: Why CEC Control Your TV?
« Reply #4 on: October 22, 2014, 09:16:25 am »
Not supporting WOL on any of the IP controllable AV devices isn't very clever. But I am sure there is a reason for it.

@Andrew: Most of the *current* JVC projectors are RS232 controllable.


totallymaxed

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Re: Why CEC Control Your TV?
« Reply #5 on: October 22, 2014, 12:12:31 pm »
Not supporting WOL on any of the IP controllable AV devices isn't very clever. But I am sure there is a reason for it.

@Andrew: Most of the *current* JVC projectors are RS232 controllable.

My information is that the main reason for this is that with the LAN port active the standby energy usage on current generation devices would ruin the TV/Amp/Proj energy usage rating. This may change next year when a few manufacturers will start to transition that functionality over to custom SOC's - once that transition is under way serial ports will begin to disappear (a cost saving) from devices to be replaced by always on IP control. It's probably 3+ years out before that becomes standard though.

All the best

Andy

Andy Herron,
Convergent Home Technologies Ltd

Read My Blog; http://ellipticalcurve.com

Contact me for Smart Home consulting advice here;
@herron on Twitter, inquiries@ellipticalcurve.com via email or PM me here.

Get a Dianemo License: http://forum.linuxmce.org/index.php?topic=8880.msg100221#msg100221
Follow us on Facebook: https://www.facebook.com/pages/Dianemo-Home-Automation/226019387454465

Sales & Info:
http://www.dianemo.co.uk

totallymaxed

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Re: Why CEC Control Your TV?
« Reply #6 on: October 22, 2014, 04:54:46 pm »
So, Andrew, if users just have the CEC from the RPI to power on the TV, does that mean they occupy one of the HDMI inputs on the TV just to do that? I'm presuming the RPI CEC can't "pass through" the signal from another device?

Pretty poor show that TVs with IP control don't implement WOL. So much for SMART.

Correct the Rpi has no HDMI pass-through on-board but other devices on the HDMI bus probably do. The HDMI device chain is in fact a 'bus' with device addresses for each device attached. So in theory your TV should be controllable wherever it is in the device chain even if the Rpi is physically connected to another devices HDMI port. However some older TV's (and possibly some new ones too) play 'free & loose' with implementing the CEC standard and this may cause the TV to not respond correctly when the Rpi is not directly connected to one of the TV's HDMI ports.

I agree re WOL not being possible on TV's is a pain. But currently its a general problem. See my earlier post though about manufacturers switching to SOC's that will enable WOL to be delivered - but its a few years away still apparently.

All the best

Andy
« Last Edit: October 23, 2014, 08:25:23 pm by totallymaxed »
Andy Herron,
Convergent Home Technologies Ltd

Read My Blog; http://ellipticalcurve.com

Contact me for Smart Home consulting advice here;
@herron on Twitter, inquiries@ellipticalcurve.com via email or PM me here.

Get a Dianemo License: http://forum.linuxmce.org/index.php?topic=8880.msg100221#msg100221
Follow us on Facebook: https://www.facebook.com/pages/Dianemo-Home-Automation/226019387454465

Sales & Info:
http://www.dianemo.co.uk