I wonder if the Reach team can comment if any type of power management is used on the Reach (Edison) module?
Specifically, I’m wondering if the Edison module can be put into a low power mode and what exactly that would mean:
how do you initiate low power mode, how do you resume
in low power mode, what peripherals are off (if any)
what would power consumption be in low power mode
There is a thread in an Intel Edison forum on this topic: Putting Edison into standby The thread contains a command to put the Edison into a different power state. The posts are from 2015-2016. There was a bug, but seems to indicate that this was fixed with the Yocto image v3.5. When I do a “uname” on my Reach, it responds with 3/10/98-poky-edison+, so I think we would be on a later version, including the power state fix.
If this is true, we could possibly lower the power consumption for a type of standby mode. I’m too afraid to try the command (“echo -n “freeze” > /sys/power/state” and the inverse “echo -n “mem” >/sys/power/state”). Updating the image was a little challenging for me, so I’m afraid to mess it up. Is anyone else brave enough to try the commands and measure power usage?
In looking at this further, it appears that you have to bring the Edison’s pin #17 PWRBTN# active (low) to wake the Edison from sleep.
It appears that the Reach module does not expose this signal - is that true?
(I looked under magnification at the 70-pin Hirose connector, but I’m not 100% sure).
If this signal isn’t exposed, then you’d have to have an ant solder a connection to pin 17, then have a way to externally ground that signal to wake the Edison.
We don’t really support this type modes. They are untested and even Intel is usually unsure whether they are supported in the kernel. The best reliable powersave you can get is disabling wi-fi.
(My Reach reference station consumes a little too much power for my solar panel and charger. One way to go is to get a larger battery and solar panel, but I don’t think I’m that far off. In reality, I don’t need to make observations overnight, so, your idea will likely work!)
On this topic, does anyone know of a way to enable a WiFi timed cutoff?
In the case of a reference station, you only need the WiFi connection for the first 5 minutes or so, and can manually disable the wifi until the next boot via ReachView. But for solar applications (in my case, weeks to months of deployment), you do run into the case where power may drop out for a period (e.g. snow on the solar panel). As the WiFi is the major power consumer, a timed wifi cutoff would be ideal for reducing power use for longer deployments…
Ideally this would happen only if no devices are connected over wifi, but for ease-of-implementation it could simply be a timer - after X minutes, disable the wifi regardless of connections.
