9

  1. Would like to enquire if anyone could list any/or all possible ways to achieve low power consumption on the raspberry pi.

  2. I have found that one could disable the USB ports of the raspberry pi . however i would require one of the usb port for my wifi usb dongle. Would it be possible to disable the remaining 3 usb ports only?

  3. What is the correct command to put the raspberry pi to sleep? and wake it up? ( I assume putting it to sleep has the same meaning/context as how one would put like a Macbook pro laptop to sleep and when the lid is flip upon its wakes up and awaits for user input)

  4. Any hardware hacks that allows to control the raspberry pi power management? (I have found SleepyPI to be expensive and was wondering if there a DIY solution or so?)

Any other suggestion for software and hardware power management control to achieve low power consumption of the raspberry pi?

Thank you for your help in advance

peekaboo
  • 97
  • 1
  • 1
  • 9

1 Answers1

4

There are two primary things you can do to reduce power consumption:

  1. Minimize the amount of power consuming peripherals attached and running.

  2. Minimize the workload. A major consumer of power is the CPU. When it is idle, it consumes less power.

That's it. The pi is a low power device compared to regular computers, but not so low power compared to many mobile devices such as smart phones. Unfortunately, there is not really much that can be done about that without adding more hardware.

What is the correct command to put the raspberry pi to sleep?

There isn't one because the hardware does not have ACPI or any other kind of power management. It is either plugged in, in which case it is on, or not.

There are commands you can issue that would work if the device did have ACPI, but it doesn't, so they won't.

Any hardware hacks that allows to control the raspberry pi power management?

No, since again, it does not have any power management.

Would it be possible to disable the remaining 3 usb ports only?

I'm not sure that doing this in the first place would really make any difference. It is like saying you would like to disconnect some empty plugs in your house to save power. If there is nothing plugged into them, they weren't using any in the first place.

Technically that's not quite true -- the USB bus itself is a microcontroller and so uses power (probably a minuscule amount when idle). However, I'm not sure that the normal recommended method for disabling USB power:

echo 0 > /sys/devices/platform/bcm2708_usb/buspower

Actually turns off the bus completely; more likely it just prevents USB devices from drawing power from the bus. Put another way, I've seen various people claiming they do this to save power, but the only evidence I've seen involves a LAN connection (the ethernet jack is on the same bus) and does not say how much simply unplugging the ethernet cable would have saved.

In any case, all the ports are on one bus, so if you disable that, you disable them all.

Community
  • 1
goldilocks
  • 60,325
  • 17
  • 117
  • 234