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Topic: Arduino Yun, power draw (Read 24983 times) previous topic - next topic

mamu

Have you check you USB cable? Have you used another device on the port/cable like  an USB stick?

dmitriyp

I am trying to figure out how to send a command to power down the linino system when I want to put my yun in "standby."
You should be able to power down the linux portion by using runShellCommand(). It also looks like pressing the YUN RST button (next to analog pin A4) powers the linux portion back up without affecting the Arduino part.

My setup was:
1. Started blink program running on Arduino, pin 13.
2. SSHd into Linino and issued `halt` command.
3. Got disconnected from SSH, Yun dropped off of the wireless network.
4. Observed that blink program was still running.
5. Pressed YUN RST button (quick press, less than a second).
6. Observed that blink program continued running uninterrupted.
7. After a minute or so, Yun came back onto the wireless network and I was able to SSH in again.

The upshot is that you should be able to trigger the YUN RST button from Arduino, perhaps by connecting it to a digital output, or less invasively, having an arduino controlled servo press it. So it should be possible to issue a halt command to Linino via runShellCommand() and then restart it using the YUN RST button. I'll do more tests and report on my results.

ShapeShifter

#17
Jan 18, 2015, 12:25 pm Last Edit: Jan 18, 2015, 12:26 pm by ShapeShifter
You should be able to power down the linux portion by using runShellCommand(). It also looks like pressing the YUN RST button (next to analog pin A4) powers the linux portion back up without affecting the Arduino part.
Sorry, but you're not actually powering anything down or back up. You're just stopping an operating system, then rebooting.

Have you done any power measurements? That will stop Linux, but will not put the AR3391 into low power mode, nor turn off any of the associated power hungry peripherals. It may reduce current a little, but odds are it won't be much.

When you "shut down" a regular computer, you are stopping the operating system, then the last thing it does is send a command to the power supply that activates special switching logic to shut off the main power supply. Shutting down Linux on the Yun does not do the same thing - the Yun has no such hardware to disable power to the Linux processor or its peripherals.

dmitriyp

Sorry, I replied on http://forum.arduino.cc/index.php?topic=192413.0 thread already, but in summary, no I haven't done the power tests yet so I realize I shouldn't have been using the phrases "power down" and "power up" in my posts.

Ok, I'll test the power draw just to confirm, but you're right. If halting linux doesn't actually power down the hardware then there's little point to doing it. Thanks for weighing in.

fsenftle

Please let me know if there's anyway to turn off the Arduino Yun WiFi.
I need to do this under the Arduino IDE with windows 7 (not LINUX).
After trying all suggestions from different posts/forums.
None worked as after 5 minutes the WiFi is enabled again.
None of these suggestions worked:
https://forum.arduino.cc/index.php?topic=189105.0
https://gist.github.com/sgk/6641198
https://gist.githubusercontent.com/sgk/6641198/raw/c6c36b2c8a9d62036b11335f6515ce3c5ce03ee6/PatchYun.ino

Please advise which forum I can ask this on, etc.
Your advise is greatly appreciated.

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