25 votes
Accepted

How to identify a Pi

On at least a Pi 3, you can turn the green (SD card activity) LED to be on constantly with the following command (as root): echo 1 > /sys/class/leds/led0/brightness Now that Pi will have the ...
stevieb's user avatar
  • 1,466
17 votes
Accepted

Turning off LEDs on Raspberry Pi 3

For the Raspberry Pi 2 you can add the following lines to /etc/rc.local: sudo sh -c 'echo none > /sys/class/leds/led0/trigger' sudo sh -c 'echo none > /sys/class/leds/led1/trigger' sudo sh -c '...
MosEisley's user avatar
  • 186
14 votes

How to identify a Pi

Shut one of them down. There should be recognizable behavior from the green light, which will eventually go out. Then put a label on that pi with its ipname. Then you can start that one up again. ...
NomadMaker's user avatar
  • 1,560
6 votes

Turning off LEDs on Raspberry Pi 3

Add the following lines to /boot/config.txt: # Disable Activity LED dtparam=act_led_trigger=none dtparam=act_led_activelow=off # Disable Power LED dtparam=pwr_led_trigger=none dtparam=...
Lasse Meyer's user avatar
6 votes

How can I control the red LED again

The latest Raspbian (using kernel 4.9) seems to have restored access to /sys/class/leds/led1 which can be used to control the PWR LED on the Pi3. NOTE this changed to /sys/class/leds/PWR in kernel 6....
Milliways's user avatar
  • 59.5k
5 votes

How to read the status of the Power-LED on Raspberry Pi 3 with Python

On the B+ (and presumably Pi2) the "PWR" LED was connected to a GPIO pin as was the APX803 voltage monitor chip. This let the LED be controlled, and (presumably) let the Pi detect under-voltage. The ...
Milliways's user avatar
  • 59.5k
4 votes

How can I control the red LED again

The activity and power LEDs on the Pi3 are now connected to a GPIO port expander hanging off I2C bus 0 (the bus you must not use on the Pi3). There is a mailbox interface to the LEDs. An (untested ...
joan's user avatar
  • 70.9k
3 votes

Turn off onboard LEDs at boot

I found a work around that simply allows me to add a few lines to the boot config file /boot/config.txt To disable ACT LED, add dtparam=act_led_trigger=none dtparam=act_led_activelow=off To disable ...
WhiskyJack's user avatar
3 votes

How to identify a Pi

I would recommend just pulling the ethernet cable, and pinging each Pi in turn. Which does then not reply? These other solutions are neat, but ping is evergreen. If for some reason you’ve filtered ...
user2497's user avatar
  • 679
3 votes

Turning off LEDs on Raspberry Pi 3

You can also add this to config.txt to turn off both Ethernet LEDs, on a Pi 3 and later: # Disable the Ethernet LEDs. dtparam=eth_led0=14 dtparam=eth_led1=14 Note that if you're using the config.txt ...
Malvineous's user avatar
  • 1,864
3 votes
Accepted

Blinking PWR when not enough current available?

It sounds like the power supply is failing to regulate and dropping out momentarily. The answer below seems to describe a similar scenario and the rpi wiki also mentions that the blinking PWR LED ...
jDo's user avatar
  • 516
2 votes

How can I control the red LED again

I haven't figured out how to get the Red LED working but I have figured out (kinda) how to get the Green LED under control. This is from user pelwell in the post here. 130 is the activity LED, so /...
kawthuldrok's user avatar
2 votes

Pi 3 on-board LEDs

Having done some research myself I can't seem to come across any resources that explain how the LEDS work. I suspect the LEDs are something that are hardwired into the Ethernet port and are not ...
Darth Vader's user avatar
  • 4,206
2 votes

rfkill* LED triggers. What does it mean?

Documentation is of course failing, but as I understood it: rfkill0 Flash on wifi activity rfkill1 Flash on bluetooth activity rfkill-any Flash on any activity (wifi ...
Ljm Dullaart's user avatar
  • 2,481
2 votes

3B+ locking up (blank video output) with red & green LEDs solid, requiring reboot. Which logs to check?

Which system log(s) do I check to see what the problem might be? It is difficult to answer the question without knowing what operating system you are using. But most modern distributions use systemd, ...
Ingo's user avatar
  • 42k
1 vote

Pi 4 booting but no green LED blinking

With Raspberry Pi OS I believe by default it only blinks with SD card activity.
joan's user avatar
  • 70.9k
1 vote
Accepted

Raspberry Pi 4: exchange power LED with activity LED

QUESTION - How to change LED function: Green LED: Power (indicate power is applied) Red LED: (indicate) Read and write activity of my SD card ANSWER: Add the following lines to your /boot/config.txt ...
Seamus's user avatar
  • 21.7k
1 vote

Bare metal LED access on RPi 4

The other answers claiming that the ACT_LED on the pi4 is not connect to the gpio is wrong. However, this was true on a previous version of the pi. One of the 3 series boards. (likely the source of ...
Myles's user avatar
  • 11
1 vote
Accepted

Program Crashes on Systemd (systemctl), Works Fine Running Manually

Changing the User from nobody to pi fixed the issue (as well as removing forking)
Chris Schlitt's user avatar
1 vote

Do the Ethernet lights show error codes?

This behavior is typical of an Ethernet interface that detects some signal on a cable, and is trying to establish a link but fails to do so due to either excessive noise, too long of a cable, a broken ...
crasic's user avatar
  • 2,983
1 vote

Bad Raspberry boards?

I would agree with the others on the SD card. Sometimes the cheapo SD cards will give you issues - I'd suggest formatting the card before flashing the image, try this: https://www.sdcard.org/...
bk79's user avatar
  • 132
1 vote

Bad Raspberry boards?

You've already indicated that you've tried different power supplies, to no avail, but have you attempted running the board with a different (known working) SD card? If you've ruled that out, I would ...
Chris G. Williams's user avatar
1 vote

Raspberry pi leds does not blink and the ic gets hot

The IC getting hot is a usual sing of electrical damage. It's likely that you inadvertently connected some pins/pads that shouldn't be connected while working on your Pi and that killed it. Make sure ...
Dmitry Grigoryev's user avatar
1 vote

Raspberry pi leds does not blink and the ic gets hot

Trying another power cable, or adding a fan makes no sense when there is no response from the LED's. You must have a serious electrical problem and in that case I would recommend you to send your Pi ...
Belekz's user avatar
  • 158
1 vote

Can someone explain what the values are and where they are found?

Basically, those #define statements are assigning human-readable names to the GPIO pins, as documented for the Pi. See the official documentation, scroll to page 90.
tlhIngan's user avatar
  • 3,372
1 vote

Green Led (ACT) is blinking for mmc0 without SD card activity

I have also asked this question Why is the green LED (ACT) blinking without SD card activity also at the Raspberry Pi Forum and received this answer: by rpdom » Wed Feb 22, 2017 8:02 pm From what I ...
Frank Breitling's user avatar
1 vote
Accepted

Replace ACT- and PWR-Led on Raspberry Pi 3

From the schematics available at www.raspberrypi.org we learn that the LED's package size is SMD 1611. I assume that is the metric code which corresponds to the imperial size of 0605. Given the ...
Ghanima's user avatar
  • 15.8k
1 vote

PiGlow script in Python doesn't work

You are missing the module piglow. I suggest you google for "Raspberry Pi Python module piglow" and see if you can find the module together with installation details.
joan's user avatar
  • 70.9k

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