How to save energy?

1st Official Post

    Hi all!

    Maybe this is a silly question, but my RPi 3b runs on 24/7 and I'm thinking if exist something I can do to save energy when I'm not watching anything.

    I have to keep it on 24/7 because I run some softwares in background that run as cron job.

    There is something that can turn Kodi on/off by TV using CEC? Because I just will need Kodi when TV will be on, but when Kodi is off this other softwares needs to keep runing.

    (I know that will depend of this softwares I use too, but consider the scenario with LIbreELEC with Kodi running and LibreELEC with Kodi not running)

    If this are not possible do you have another ideas?

    I imagine that when I'm not watching anything the LibreELEC already save energy, but I'm think if this idea will save more.

    And please tell me if it's a stupid idea ^^

    Thanks!

    • Official Post

    Personally, I wouldn't bother. The RPi3B probably uses around £7 -> 10 per year to run 24/7. Costs are depending on the efficiency of your PSU and cable, charges for the electricity and how active the RPi actually is. Minus the advantage of the heat it produces to heat the house :)

    This, I believe, is equivalent to leaving a 5W LED light on 24/7.

    Small savings *could* be made by turning HDMI off when not in use and turn off LED's. Better savings could be made by turning WIFI and BT - especially if not used.


    You'd be better off turning your heating off for one hour.

    Thanks Iridium, I thought that will be the answer.

    Quote from Iridium

    Small savings *could* be made by turning HDMI off when not in use and turn off LED's. Better savings could be made by turning WIFI and BT - especially if not used.

    When you say turning HDMI off you're talking about what? And how can I turn LED's off?

    The BT is already disabled, since I don't use it. Internet is needed for this apps in background, so can't disabler WIFI.

    • Official Post

    In theory you can switch HDMI off and on by using the "tvservice" command with the appropriate options. That would save energy. I was playing around with that command a couple of month ago, but I was not successful to switch HDMI on after switching it off. Maybe it's working with the current LE version.

    Or you could buy another RPi, and run one of them headless (Raspbian) for your CRON services. Install a power button on the other one, where you run LE.

    Quote from Da Flex

    In theory you can switch HDMI off and on by using the "tvservice" command with the appropriate options. That would save energy. I was playing around with that command a couple of month ago, but I was not successful to switch HDMI on after switching it off. Maybe it's working with the current LE version.

    Or you could buy another RPi, and run one of them headless (Raspbian) for your CRON services. Install a power button on the other one, where you run LE.

    I found this, but how I can do this automatically for when I turn tv on?

    You second idea is good, and I think (not sure) that I can turn Kodi (and LibreELEC, I think) on/off automatically by CEC options. But for the moment I will not buy another RPi,

    • Official Post
    Quote from edjalmo

    I found this, but how I can do this automatically for when I turn tv on?

    The major problem is that you disable CEC when you switch HDMI off.

    If you're familiar with electronics, you could install an infrared receiver element on your RPi. So you can turn HDMI on by IR code.

    An easier solution is to install a push button, and listen to it by an autostart script (similar to the well known power button on RPi).

    Take into account that an RPi Zero is cheap, and you can even run LE on it just for CRON jobs.

    To run LE headless, switch HDMI off from autostart.sh. As I already mentioned, switching off works.

    This isn't the most graceful way but still it does the job;

    In the bedroom i run a small bash script with cron every night at 03:00

    Code
    systemctl stop kodi
shutdown now

    At 03:30 the "smart power plug" cuts power to the RPi.

    Day after, the power plug scheduler starts/power on the RPi at 16:00.

    (If necessary, it kan be started with remote as well...)

    Quote from Jocke.Sve

    This isn't the most graceful way but still it does the job;

    In the bedroom i run a small bash script with cron every night at 03:00

    Code
    systemctl stop kodi
shutdown now

    At 03:30 the "smart power plug" cuts power to the RPi.

    Day after, the power plug scheduler starts/power on the RPi at 16:00.

    (If necessary, it kan be started with remote as well...)

    I do something similar, but just to reboot Kodi. Since I use another programs in background and If I not reboot Kodi will be slowly with the past of days. What I wished is do this, automatically, based on tv power on/off, and just Kodi, not LibreELEC.

    But I think this is impossible.

    • Official Post
    Quote from edjalmo

    I do something similar, but just to reboot Kodi. Since I use another programs in background and If I not reboot Kodi will be slowly with the past of days. What I wished is do this, automatically, based on tv power on/off, and just Kodi, not LibreELEC.

    But I think this is impossible.

    I think it could work. Use the RPi always-on for CRON, and switch Kodi / tvservice (HDMI) on / off with a button connected to GPIO.