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power management question

2019-01-24 by: wes
From: wes 
------------------------------------------------------
I have an odd problem I'm trying to solve. I have an older flat panel TV
that I'm using as a computer monitor for a Linux system. The TV does not
(appear to) support any sort of auto-standby mode when it gets no signal,
so it just displays the "no signal" notice 90% of the time.

Currently I have set it up on a power strip with a motion sensor, so at
least it's not spending nights & weekends on for no reason. I would like to
cut this down further.

I've looked into a number of options. The TV supports HDMI-CEC control
codes, but I haven't found any consumer-grade video cards that implement
that feature other than in a Raspberry Pi type of device. If I could find
such a card, that would be ideal.

I also have a power strip controlled by a USB cable - if there's power to
the USB plug, it turns on the outlets. However, it seems that in kernel
2.6.38 or so, the option to arbitrarily set the state of a USB port (or
whole controller) was removed. So I need to find something in the system
that I can power on/off at will. Preferably something that turns off when
the display turns off. I had thought about cutting into the video cable and
splicing a relay onto the power circuit... but by the time I got that
going, I would have spent more than the cost of a ready-made device that
already exists to do what I'm trying to do. (
https://www.pulse-eight.com/p/104/usb-hdmi-cec-adapter if you're curious)

Ideas?

thanks,
-wes
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=============================================================== From: Ed King ------------------------------------------------------ I'd replace it with a teletype ________________________________ From: Chugalug on behalf of wes Sent: Wednesday, January 23, 2019 7:02:04 PM To: CHUGALUG Subject: [Chugalug] power management question I have an odd problem I'm trying to solve. I have an older flat panel TV th= at I'm using as a computer monitor for a Linux system. The TV does not (app= ear to) support any sort of auto-standby mode when it gets no signal, so it= just displays the "no signal" notice 90% of the time. Currently I have set it up on a power strip with a motion sensor, so at lea= st it's not spending nights & weekends on for no reason. I would like to cu= t this down further. I've looked into a number of options. The TV supports HDMI-CEC control code= s, but I haven't found any consumer-grade video cards that implement that f= eature other than in a Raspberry Pi type of device. If I could find such a = card, that would be ideal. I also have a power strip controlled by a USB cable - if there's power to t= he USB plug, it turns on the outlets. However, it seems that in kernel 2.6.= 38 or so, the option to arbitrarily set the state of a USB port (or whole c= ontroller) was removed. So I need to find something in the system that I ca= n power on/off at will. Preferably something that turns off when the displa= y turns off. I had thought about cutting into the video cable and splicing = a relay onto the power circuit... but by the time I got that going, I would= have spent more than the cost of a ready-made device that already exists t= o do what I'm trying to do. (https://www.pulse-eight.com/p/104/usb-hdmi-cec= -adapter if you're curious) Ideas? thanks, -wes X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KQ2h1Z2FsdWcg bWFpbGluZyBsaXN0CkNodWdhbHVnQGNodWdhbHVnLm9yZwpodHRwOi8vY2h1Z2FsdWcub3JnL2Nn aS1iaW4vbWFpbG1hbi9saXN0aW5mby9jaHVnYWx1Zwo=

=============================================================== From: Jason Brown ------------------------------------------------------ Could you use something like LIRC http://www.lirc.org/ to send power on / power off commands to the television via IR? --Jason

=============================================================== From: wes ------------------------------------------------------ This is clever, though in half an hour of searching I have not been able to find good candidates for IR transmission hardware. It seems that if I want it cheap, I have to build it myself. Which I can do, but this particular project doesn't really call for that. And to get off-the-shelf, I'd have to spend more than the USB CEC device would cost. This does make me wonder if it has an IR input port. I'll have to pull it off the wall and check. If so, can I just run an audio patch cable from a sound card to the IR input? hmmmmm..... -wes

=============================================================== From: Dan Lyke ------------------------------------------------------ Looks like if you've got a 96KHz sound card you might be able to hook up an IR LED to that and use LIRC. It's an AVR, an LED and some driver circuitry, or http://www.irblaster.info/usb_blaster.html https://www.irdroid.com/usb-infrared-transmitter/ But I don't know what qualifies as "cheap" for you.

=============================================================== From: Dan Lyke ------------------------------------------------------ Hmmmm... $17 + a Pi: https://alexnld.com/product/ir-infrared-receiver-and-transmitter-expansion-board-for-raspberry-pi/

=============================================================== From: wes ------------------------------------------------------ $24 is not bad at all. Though it occurs to me after thinking about it, the same IR command is used for on and off, so there is a good chance of getting out of sync. Pi has the CEC stuff in it already, so by the time it gets complex enough to use that, it's already done. The CEC gizmo is $45. which is not out of my budget. I just wanted to make sure I'm not missing something simple before I go that route. -wes

=============================================================== From: Jason Brown ------------------------------------------------------ Even though your remote only has one button and sends the same command for on and off, most TV's also support discreet commands for those functions too. Here is some stuff related to the TV-B-Gone project: http://www.makery.info/en/2015/04/07/bricole-it-yourself-la-telecommande-qui-eteint-toutes-les-teles/