My research began with the original thread on the Raspi forums: http://www.raspberrypi.org/phpBB3/viewtopic.php?f=63&t=6050&p=291334&hilit=watts+power#p291334
To summarize what we've learned there, the total consumption of a Raspberry Pi is probably not more than:
4 W * 24 h = 96 Wh (I guess that's 346 kJ) (note this is an energy value, not ...
You can enter the following three xset commands
xset s off # don't activate screensaver
xset -dpms # disable DPMS (Energy Star) features.
xset s noblank # don't blank the video device
file (You should insert these after the first line).
I had the same issue. At raspberry pi forum I found this:
You need to edit your script that's starting X. In the default build with lightdm the file to edit is
in the SeatDefaults section it gives the command for starting the X server which I modified to get it to turn off the screen saver as well as dpms
Yes, most (but not all!) USB power banks are capable of powering a Raspberry Pi, since they usually have an output voltage of 5 V. And yes, by using a (quite large) 50 Ah power bank, you can definitely expect your Pi to run for at least 24 h. See the long answer below for reasoning and further relevant aspects.
According to actual ...
The main issue is the fact that the RaspberryPi's hardware design actually does not offer a power-off circuitry. So the answer is that without additional hardware it is not possible to power the RaspberryPi down using that keyboard button.
While the keyboard event could certainly be used to halt the system that would do no good as power consumption is only ...
The wireless device goes to sleep after a period of no activity. It's a powersaving scheme.
You need to turn off the powersave feature of wlan0.
I'm using an edimax wireless usb receiver:
Bus 001 Device 005: ID 7392:7811 Edimax Technology Co., Ltd EW-7811Un 802.11n Wireless Adapter [Realtek RTL8188CUS]
It uses the 8192cu module in the kernel.
To turn ...
As long as the power bank outputs 5V it will power the Pi.
It claims 50000mAh so it claims 2.5 amps per hour for 24 hours. Assume it will deliver half that so 1.25 amps for 24 hours.
If that is enough or not will depend on what you have connected and what the Pi is doing.
Unplug it from mains power :)
But seriously: the Pi has a "base" power usage when run headless, without anything plugged in (no monitor, no usb devices, just the power supply). Use a Kill-A-Watt meter to measure the powerusage of this setup. Then do the following:
If you want to further reduce this power usage, you can look into disabling a few things.
I am running a Raspberry Pi2 with a 2TB Western Digital element hard disk mounted as root disk (apm set to 254 - effectively disabling standby) via a Y-connector.
Using a USB VA meter (eBay link - LCD USB Charger Current Voltage Detector Tester Monitor Meter For Phone Tablet) I measured (with both the USB HDD and Raspberry Pi2) 5V and about 0.7A.
Your solution is simple, use an inverter, and a start up script. When The script runs, have an IO pin go high, which will force the LED off. When the OS is off, and the script driving the IO pin is off, the LED will illuminate.
I still haven't made it back to my Pi location, but it may be possible to do this without an inverter.
You would add you script ...
Yes, should do
Just double checking the datasheet of the MT3608:
if using AA rechargables instead of batteries, mind the lower voltage (cell voltage 1.2 V), but for two cells in series still above the lower lockout voltage (2 V) of the MT3608
at very low input voltages the efficiency could be lower than 80 %, the datasheet (p. 5) lists 80 % at 3 V and a ...
I believe the GPU is identical in all Pis and makes up 95% of the silicon. The remaining 5% is used by the relatively puny ARM core(s).
It's shutting down just fine. If you check the schematic, you'll see there is no power management. From USB in to the SoC is just copper (and a fuse), so the chip stays powered up even when it's shut down.
What do I do once I have run shutdown -h now?
Just remove the USB from the socket.
No need to add other GPIO pins. You could just use the same pins for your halt-button.
Here is some python code that will poll pin 5. When the button is presses pin 5 is pulled to ground (pin 6), and the code will read a LOW. In that case is will run the halt command
import RPi.GPIO as GPIO
Other things you may want to search for include disabling the LEDs, disabling HDMI out and 'nohz' kernel option to alter the tick interrupts from periodic clocks.
Articles I've seen also suggest that Kill A Watt measurements are pretty inaccurate at low current levels, use a bench meter if you have one available.
This article has a good few handy links in ...
After doing some experimentation of my own I done the following to experiment:
USB to TTL / Debug cable with 5V via multimeter.
Normal boot at login screen with just the power and network connected was about 420-380Ma
I first turned off networking via /etc/init.d/networking stop and then the chip by echo 0 > /sys/devices/platform/bcm2708_usb/buspower ...
No and No.
The Pi has no way of waking itself up apart from a hardware reset button, which can wake the Pi up from a halt state, i.e. it will reboot the Pi.
You can modify the hardware and use switching regulators rather than the linear regulators that the Pi uses out of the factory for some more energy saving.
Apart from that though, you won't get ...
You will need peripheral hardware to turn the pi on and off, since it does not have a power button. The good news is that it is fairly simple to build one, and not very expensive. Have a look at: http://www.raspberry-pi-geek.com/Archive/2013/01/Adding-an-On-Off-switch-to-your-Raspberry-Pi
The kernel already consumes negligible power. The software loaded on the pi would be the ones munching the most power because of processor time (Apache, databases, networking, etc.)
Here are some tips to reduce power consumption even further:
Disable unneeded software services on the Pi.
Avoid unnecessary peripherals (USB devices, GPIO accessories)
Yes. Here's what I use:
hdparm -B 127 /dev/sda
hdparm -S 242 /dev/sda
From the command line as the pi user you would have to add sudo there. The first line enables spin down. The second one sets it to happen after 1 hour of inactivity. This is documented in man hdparm. You may need to sudo apt install hdparm first.
Beware that's the device node (sda),...
Current (amperage) doesn't work like that. The device draws the current it requires, and the power supply needs to provide that or higher. For example, if you were to switch to a 2A (2000mA) supply, it would operate fine (assuming 5V of course).
So the answer is there is no limit. Just make sure you provide the appropriate voltage and at least the actual ...
No, it is not possible to enable/disable or power down any single USB port. The hub providing the different ports is connected to one root USB port, thus it's none or all.
Ok, but is it possible to disable root USB port?
For the B-type it should be possible to disable the USB-Hub (see http://babaawesam.com/2014/01/24/power-saving-tips-for-raspberry-pi/ ) ...
I have not measured it myself, but this person claims the pi draws about 110 mA after shutdown, i.e., when the OS has halted and just the red PWR led glows.
Figures regarding the number of amp-hours in a car battery seem to vary quite widely; if we assume 50, then that's 50 / .11 ~= 454.5 hours such a battery should last with an inoperative pi attached. Of ...
The conventional solution to this problem (as others have pointed out) is a Watchdog. There is a watchdog daemon, which you can install, but no one can design it for you, as this depends on what application you are running. Try reading its documentation.
You would probably be better to use a simple external timer (any solution which relies on software ...
Yes it is safe. The raspberry pi will only draw the current it requires. I use a 1.2A power supply and my raspberry pi draws only 0.53A while running a stereo vision algorithm in the background. This is what i used to test it:
A higher ampere rating on a charger would give you more flexibility such as when adding more usb type peripherals such as a Mouse, ...
The Pi draws about 300mA at 5V, plus whatever your GPS unit would draw. Ignoring the small losses associated with a (switching) step-down converter. Say a total of 2W. That would be equivalent to drawing 1/6A at 12V. If you have a 60Ah battery, it would last for 360h, or 15 days, give or take. So long as you move your car more than once a week, you should ...
The raspberry pi hardware has no power management capability. Period. End of story. It does not have a sleep or suspend mode. It cannot not even be turned off. There's either power (plugged in), or there isn't (not plugged in).
When you shutdown the system, the software stops, meaning there is now no way to get it to do anything again. However, the "...