4 ms·

Very interesting. Still far from solar-powered territory for outdoor projects, for example. Unless there were a way to wake the pi very easily. However, the

Very interesting. Still far from solar-powered territory for outdoor projects, for example. Unless there were a way to wake the pi very easily. However, the raspberry pi includes no power management whatsoever; it's either off or on[1]. Why not? Does the chip not support it? --> Note that the article specifically calls out disabling USB, disabling ethernet (not relevant here), and disabling video output if not using it. I wonder if the author could try disabling HDMI to see if power is reduced.... This can be mitigated if there were a way to boot quickly on demand. See this writeup on sleepypi, an expansion-board that does just that:[2] So it should be possible to wake on demand by powering up and going through a boot cycle. Since the hardware is SO very fixed (not going to change short of ripping parts of the board off) I wonder why the boot time couldn't be further reduced...what really takes 10 seconds, during which the SD card could have read 200 MB or so? It's nearly enough time to wake from hibernation, were that supported. (SD card bus speed is limited to reading 20 MB/second or so). I'm sure it could be improved. This other write-up mentions using the previous generation for up to 24 hours for remote-location time-lapse photos [3] - also contains an interesting idea about underclocking. Not sure if this suggestion is relevant, possible, or works. [1] No sleep mode on pi: http://raspberrypi.stackexchange.com/questions/4773/raspberry-pi-sleep-mode-how-to-avoid http://raspberrypi.stackexchange.com/questions/4773/raspberr... [2] * Pi and SleepyPi: http://marktmarshall.com/2014/08/experimenting-with-raspberry-pi-power-management/ http://marktmarshall.com/2014/08/experimenting-with-raspberr... * An interesting FAQ on SleepyPi: http://spellfoundry.com/sleepy-pi/sleepy-pi-faq/ http://spellfoundry.com/sleepy-pi/sleepy-pi-faq/ [3] Powr saving on raspberry pi A in remote installations: http://babaawesam.com/2014/01/24/power-saving-tips-for-raspberry-pi/ http://babaawesam.com/2014/01/24/power-saving-tips-for-raspb...

bootload 11y ago
" I wonder if the author could try disabling HDMI to see if power is reduced...." from comments ~ http://www.midwesternmac.com/comment/3216#comment-3216 http://www.midwesternmac.com/comment/3216#comment-3216 in this article, "Controlling both the PWR and ACT LEDs on the Raspberry Pi 2" ~ http://www.midwesternmac.com/blogs/jeff-geerling/raspberry-pi-zero-power http://www.midwesternmac.com/blogs/jeff-geerling/raspberry-p...
- throwawydfje 11y ago
  (could you clarify why you include the second link? Your second link is our article link.) The comment that you mention mentions savings of "28ma" - could it really be so high? This is hard to believe, or hard to believe that it would translate the raspberry pi zero, as our article link says the idle is 50-70 mA (third photo caption on page) - so if true and the same for this board, disabling HDMI would reduce current by up to 56%! However, on the other hand that might not be true at all. Perhaps the A has a dedicated chip for HDMI, whereas this chip drives it directly; or perhaps the hearsay on current savings from the HDMI is simply wrong. I've submitted a version of this comment as a comment to the author's blog, since he's all set up to investigate. (I think the post is pending moderation.) Probably there will be 0 power savings. EDIT: Thanks, author!
  - geerlingguy 11y ago
    I just tested this three times, and it looks like it's right around 30 mA saved, so the rumors are true! I'm going to tinker a little bit and see how low I can get the power consumption (disable HDMI, disable LED, and just have Pi running by itself). I'll post back here with more details.
    - throwawydfje 11y ago
      Wow! That is an astounding difference. Thanks for your quick action. If your numbers are correct looks like you just reduced idle usage by close to 50% - 0.2 watts to 0.1 watts or something - if a solar panel has to get through fog and night-time on an attached battery, that is a huge difference!
      - geerlingguy 11y ago
        Running barebones I can get down to 40 mA at idle. Almost Arduino territory!
        throwawydfje 11y ago

bootload 11y ago

" I wonder if the author could try disabling HDMI to see if power is reduced...." from comments ~ http://www.midwesternmac.com/comment/3216#comment-3216 http://www.midwesternmac.com/comment/3216#comment-3216 in this article, "Controlling both the PWR and ACT LEDs on the Raspberry Pi 2" ~ http://www.midwesternmac.com/blogs/jeff-geerling/raspberry-pi-zero-power http://www.midwesternmac.com/blogs/jeff-geerling/raspberry-p...

throwawydfje 11y ago
(could you clarify why you include the second link? Your second link is our article link.) The comment that you mention mentions savings of "28ma" - could it really be so high? This is hard to believe, or hard to believe that it would translate the raspberry pi zero, as our article link says the idle is 50-70 mA (third photo caption on page) - so if true and the same for this board, disabling HDMI would reduce current by up to 56%! However, on the other hand that might not be true at all. Perhaps the A has a dedicated chip for HDMI, whereas this chip drives it directly; or perhaps the hearsay on current savings from the HDMI is simply wrong. I've submitted a version of this comment as a comment to the author's blog, since he's all set up to investigate. (I think the post is pending moderation.) Probably there will be 0 power savings. EDIT: Thanks, author!
- geerlingguy 11y ago
  I just tested this three times, and it looks like it's right around 30 mA saved, so the rumors are true! I'm going to tinker a little bit and see how low I can get the power consumption (disable HDMI, disable LED, and just have Pi running by itself). I'll post back here with more details.
  - throwawydfje 11y ago
    Wow! That is an astounding difference. Thanks for your quick action. If your numbers are correct looks like you just reduced idle usage by close to 50% - 0.2 watts to 0.1 watts or something - if a solar panel has to get through fog and night-time on an attached battery, that is a huge difference!
    - geerlingguy 11y ago
      Running barebones I can get down to 40 mA at idle. Almost Arduino territory!
      - throwawydfje 11y ago