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MartinPi
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Bought new Pi Zero, no LED light showing...

Sun Nov 29, 2015 4:51 pm

Hi everyone, new Pi user here. Got my Raspberry Pi Zero from the MagPi magazine. Have one question before I start buying a load of addon so (such as keyboard, mouse, HDMI, SD card...), when I plug in using a BlackBerry phone charger (micro USB), there is no indication to it working. The light doesn't show.

I have also incerted a micro SD card into my Pi (although it never had any data on it that would be readable, as it was taken straight out a phone) just to see if I could get any indication of my model working. Again, no light showed.

Do I have to buy an SD card, add the NOOBS software, insert the card to the Pi Zero, then power it up to get a light and now that my model is working fine?

Many thanks, a quick reply would be amazing so I can order as soon as possible.
Raspberry Pi 3 32GB with 32-inch Monitor
Rasberry Pi Zero 32GB

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mahjongg
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Re: Bought new Pi Zero, no LED light showing...

Sun Nov 29, 2015 4:54 pm

Yes, the PI zero does NOT have a power LED, only an activity LED which becomes only active after the PI is booting.
For booting just MUST use a SD-card (8GB minimum) correctly programmed with NOOBS.
If you have problems getting the zero to boot, please read the boot problem sticky post, in "troubleshooting".

danthetucker
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Re: Bought new Pi Zero, no LED light showing...

Tue Dec 01, 2015 5:20 pm

You say Pi Zero needs an 8GB Micro SD card? I have been trying to boot mine with a 4GB Micro SD, will this not work? I am currently troubleshooting as to why it won't boot, not sure if it's power (iPad charger) or lack of Keyboard/Mouse or SD card. Will i get any video output with just HDMI and power connected?

Thanks, new to the Pi :)

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rpdom
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Re: Bought new Pi Zero, no LED light showing...

Tue Dec 01, 2015 5:40 pm

danthetucker wrote:You say Pi Zero needs an 8GB Micro SD card? I have been trying to boot mine with a 4GB Micro SD, will this not work? I am currently troubleshooting as to why it won't boot, not sure if it's power (iPad charger) or lack of Keyboard/Mouse or SD card. Will i get any video output with just HDMI and power connected?
You will not get any output at all without a suitable SD card with the correct software installed. The "firmware blob" that gets loaded first from the card tells the Pi what a video output is and what to do with it. Then it starts to boot the OS.

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NikThePlumber
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 8:45 pm

Just for reference, I was stumped by why my new Pi Zero appeared to be dead on arrival. It turned out that, as mentioned above, my SD card did not have a bootable image on it (it's a long story). I was eventually able to install Raspbian jessie lite and boot with no problems.

Many thanks to Phil Howard at Pimoroni for pointing me in the right direction.

emma1997
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 8:59 pm

danthetucker wrote:You say Pi Zero needs an 8GB Micro SD card?
Currently I am using 1gb SD on both my RPi2 and Zero so that's not quite true. It all depends on the OS version. IMO Jessie Lite ain't that "lite" and DietPi... well, beware anything with the word Diet... specially soda. I used 1gb initially because they were in my junk box but then noticed they take a fraction as long to load. So now I've actually ordered a few more. Strangely 1gb and 2gb cost more than 8gb which is the recommended size for beginners anyway.

Also odd that the ACT light on my RPi2 always comes on with no card but not with the Zero. Somethings different.
Last edited by emma1997 on Sun Jan 03, 2016 9:11 pm, edited 1 time in total.

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rpdom
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 9:04 pm

emma1997 wrote:Also odd that the ACT light on my RPi2 always comes on with no card but not with the Zero. Somethings different.
Not really odd. The LED on the zero is inverted compared to the B+ and Pi2. Those have some extra components to make the LED behave the way it does. Those were left out of the zero to save cost.

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NikThePlumber
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 9:07 pm

I mostly use GPIO and Python so don't really touch most of what the OS can do, but yeah, the download wasn't exactly "lite".

I was quite surprised to find that there was no indicator light of any kind until during boot. My issue was actually image related, but my first instinct was that the hardware had arrived bricked as it was entirely unresponsive. I'm hardly a noob these days (although I do feel like one today!), but this isn't the same kind of instantly obvious that I've had with my other Pi.

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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 9:16 pm

rpdom wrote: Not really odd. The LED on the zero is inverted compared to the B+ and Pi2. Those have some extra components to make the LED behave the way it does. Those were left out of the zero to save cost.
So when the light is OFF that means the card is being accessed? :shock: Well that explains why it's on constant after booting even when there is no activity. Very dangerous for those like me who often do not do a controlled shutdown. Looks like some firmware fixes might be in order.

Note to self: Now power down only when the light is steady ON.

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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 9:21 pm

emma1997 wrote:
rpdom wrote: Not really odd. The LED on the zero is inverted compared to the B+ and Pi2. Those have some extra components to make the LED behave the way it does. Those were left out of the zero to save cost.
So when the light is OFF that means the card is being accessed? :shock: Well that explains why it's on constant after booting even when there is no activity. Very dangerous for those like me who often do not do a controlled shutdown. Looks like some firmware fixes might be in order.

Note to self: Now power down only when the light is steady ON.
Balderdash and poppycock. The ACT light works exactly like every other Raspberry. The firmware even winks it 10 times during a controlled shutdown/poweroff when it's safe to pull the power.
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emma1997
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 9:38 pm

Sorry but not in my case. I pulled standard 8gb SD with regular Jessie from one of my working RPi2 and plugged it into a Zero. After blinking for the expected 30s or so it came on solid and stayed that way for at least half hour or so. YMM and obviously does V.

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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 9:51 pm

There must be a process that's thrashing your filesystem to death.
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 10:04 pm

Well it don't thrash when I put it back into the RPi2. And I don't see any reason it would since there have been no mods to this image. Maybe they did (retroactively) follow my advice to fix the firmware.

Does your light come on with no card? Rpdom explanation makes much more sense to me. Unless they are already shipping different hardware versions which does not make sense.

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NikThePlumber
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 10:10 pm

Without a card in I get no activity at all.

gregeric
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 10:20 pm

DougieLawson wrote:
emma1997 wrote:
rpdom wrote: Not really odd. The LED on the zero is inverted compared to the B+ and Pi2. Those have some extra components to make the LED behave the way it does. Those were left out of the zero to save cost.
So when the light is OFF that means the card is being accessed? :shock: Well that explains why it's on constant after booting even when there is no activity. Very dangerous for those like me who often do not do a controlled shutdown. Looks like some firmware fixes might be in order.

Note to self: Now power down only when the light is steady ON.
Balderdash and poppycock. The ACT light works exactly like every other Raspberry. The firmware even winks it 10 times during a controlled shutdown/poweroff when it's safe to pull the power.
Sorry Dougie, you are mistaken, withdraw the b & c statement, it's exactly as Emma has observed. The LED on the Zero is inverted, blinks OFF for activity rather than ON. So steady ON reflects no card writes. Yes it may wink similarly on fault/shutdown, but otherwise it's arsewise up.

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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 10:23 pm

NikThePlumber wrote:Without a card in I get no activity at all.
Yes, if you read the posts that is to be expected. Unlike other Pi it is reversed so off unless activated by boot code. What is a mystery is Dougies claim it behaves the same as other Pi. It should be possible with minor firmware mods to make it behave the same once booted which would be, as Martha says, "a GOOD thing".
Last edited by emma1997 on Sun Jan 03, 2016 10:27 pm, edited 3 times in total.

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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 10:25 pm

emma1997 wrote:Well it don't thrash when I put it back into the RPi2. And I don't see any reason it would since there have been no mods to this image. Maybe they did (retroactively) follow my advice to fix the firmware.

Does your light come on with no card? Rpdom explanation makes much more sense to me. Unless they are already shipping different hardware versions which does not make sense.
I've never tried it with no card. But it looks like I was wrong, my zero is mostly idle it's running a python program that wakes up every thirty seconds and reads an NFS file across my network then writes the results on a MAX7219 controlled LED display. The green LED is on solid.
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 10:29 pm

Mystery solved. Wish I had the smarts to make the right changes in Rasbian to cause it to behave the same once booted.

gregeric
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 10:36 pm

emma1997 wrote:Mystery solved. Wish I had the smarts to make the right changes in Rasbian to cause it to behave the same once booted.
That is possible, either in config.txt or device tree overlay, can't recall right now.

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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 10:37 pm

emma1997 wrote:Mystery solved. Wish I had the smarts to make the right changes in Rasbian to cause it to behave the same once booted.
There are some controls in /boot/config.txt but we'll need to test whether they work on the Zero.

Code: Select all

dtparam=act_led_activelow=on
The crazy thing is the GPU firmware knows it's a Zero so should set that as default (if it works).
Github issue opened at https://github.com/raspberrypi/firmware
Last edited by DougieLawson on Sun Jan 03, 2016 10:45 pm, edited 1 time in total.
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 10:42 pm

Progress. I can verify it does work. Thanks.

Now if only there was some way to incorporate into the main core a routine to sense what hardware is running so we didn't need a special image.

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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 10:45 pm

There was some discussion here as to whether or not enable "normal" ACT led behaviour, but it looks like they're staying with the inverted behaviour so that the ACT led acts as a pseudo power-on led too.

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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 10:46 pm

gregeric wrote:There was some discussion here as to whether or not enable "normal" ACT led behaviour, but it looks like they're staying with the inverted behaviour so that the ACT led acts as a pseudo power-on led too.
We'll have to wait and see what they say about my new github issue.
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 11:11 pm

if the SD card is OK and can boot the Pi Zero the led comes on a second or two after applying power. It flashes off when the SD card is accessed, opposite to all other Pi's. It stays lit when idle and the SD card is not being accessed.

If the led does not light at all the SD card the image may not have been correctly installed on the SD card or may not have a kernel version installed new enough to use on the Pi. It is possible that the Pi zero could be broken but this is extremely unlikely.

The behaviour of the led when using a command to shutdown/power off is dependent on whether you are using a Wheezy or Jessie kernel.

If you have Wheezy installed using commands sudo halt, sudo poweroff or sudo shutdown -h now the led will flash 10 times and then turn off and the Pi will shutdown/halt.

If you have Jessie installed using command sudo halt the led will flash off a couple of times and then stay permanently on after it has halted. Using commands sudo poweroff or sudo shutdown -h now the led will flash 10 times and then turn off and the Pi will shutdown/halt.

I find the way it behaves at the moment just fine. The led behaves like a PWR and ACT led combined. What is the problem with it flashing off or flashing on to the indicate the SD card is being accessed. With the led permanently lit when the SD card is not being accessed it behaves like a PWR led so you know it is powered. If the behaviour is changed to emulate the ACT led on previous Pi's the led will be off even when the Pi Zero has power applied, so is it really powered up or not. You won't know.


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emma1997
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Re: Bought new Pi Zero, no LED light showing...

Sun Jan 03, 2016 11:36 pm

Aside from the fact that normal is normally a good way for any normal device to behave normally, I find ACT off a good way to judge if it's ok to power down. And according to behavioral blink off is much harder to detect than blink on. But mostly there is not always a way to enter commands and I don't like having to ask my machines permission for anything anyway. They are not the BOSS of me. Or in any case shouldn't be. It's one reason I hate Windoze so much.

I find it very annoying that the Xbian developers thought it was a good idea to turn off the red power light when unit is on. What is going on in these guys heads?

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