FriendlyELEC-Forum

Board: NanoPI Neo 512, version 1.31
OS: xenial-4.14 2019/10/18
SD Card: Brand new microSDHC UHS-I Toshiba 16GB
Power: 2A powered USB HUB.

Hi, just a question about the Blue LED (stat ?) on a NanoPI Neo board.

Everything seems to work OK...
After boot, the Blue LED (stat ?) blink constantly without stop...
Approximate 2 blinks in 1 second... then about 1 second pause, then blink again...
Keep repeating this blinking pattern all the time...

What is the meaning of this Blue Led Blink?
Is it signaling something wrong?
Is there a setup need to be done?

Thanks,
Valter

Thats OK - this is the "Heartbeat" Signal

guidol wrote:
Thats OK - this is the "Heartbeat" Signal

guidol, thanks for the reply...

Is there infos about how it works and perhaps how to disable it and use the LED for other purpose?

Regards,
Valter

ecolezen wrote:
Is there infos about how it works and perhaps how to disable it and use the LED for other purpose?

for using it as HDD-Led for the scard (mmc0) use:
echo 'mmc0' > /sys/class/leds/nanopi:blue:status/trigger

for turning it off:
echo 'none' > /sys/class/leds/nanopi:blue:status/trigger

other options can be found with:
more /sys/class/leds/nanopi:blue:status/trigger
none rc-feedback kbd-scrolllock kbd-numlock kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock kbd
-ctrllock kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock kbd-ctrlrlock usbport [mmc0] mmc1 d
isk-activity disk-read disk-write ide-disk mtd nand-disk heartbeat cpu cpu0 cpu1 cpu2 cpu3 default-on
panic 0.1:01:link 0.1:01:100Mbps 0.1:01:10Mbps

the same options you can use with the green led:
echo 'heartbeat' > /sys/class/leds/nanopi:green:pwr/trigger

but none, heartbeat and mmc0 are the most useful options

guidol wrote:

ecolezen wrote:
Is there infos about how it works and perhaps how to disable it and use the LED for other purpose?

for using it as HDD-Led for the scard (mmc0) use:
echo 'mmc0' > /sys/class/leds/nanopi:blue:status/trigger

for turning it off:
echo 'none' > /sys/class/leds/nanopi:blue:status/trigger

other options can be found with:
more /sys/class/leds/nanopi:blue:status/trigger
none rc-feedback kbd-scrolllock kbd-numlock kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock kbd
-ctrllock kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock kbd-ctrlrlock usbport [mmc0] mmc1 d
isk-activity disk-read disk-write ide-disk mtd nand-disk heartbeat cpu cpu0 cpu1 cpu2 cpu3 default-on
panic 0.1:01:link 0.1:01:100Mbps 0.1:01:10Mbps

the same options you can use with the green led:
echo 'heartbeat' > /sys/class/leds/nanopi:green:pwr/trigger

but none, heartbeat and mmc0 are the most useful options

Thanks again...
I just set another SD with a new ARMBIAN Buster for the NanoPI Neo...
It seems that the "heartbeat" is also there, on the new ARMBIAN...

I had an old ARMBIAN version on the Neo, the old version does not have this "I am alive" signal...

Some months ago I had one idea when I was setting a RPI Zero as OTG Dongle,...
... to use the power LED as a "General Morse Code Display" as a primitive form of visual interface, so it can be used for small short "messages"...

I had not yet done it, but I think it is feasible and perhaps useful in real life situations...
Perhaps a "Morse Display LED for SBC" can be born out of this trick, if it works...

Regards,
Valter

ecolezen wrote:
... to use the power LED as a "General Morse Code Display" as a primitive form of visual interface, so it can be used for small short "messages"...

for turning LED steady on:
echo 'default-on' > /sys/class/leds/nanopi:blue:status/trigger

for turning LED off:
echo 'none' > /sys/class/leds/nanopi:blue:status/trigger

between you should use the sleep command with
sleep 1
for a long light

or
sleep 0.5
for a short light

you also need a pause between every light-pulse

guidol wrote:

ecolezen wrote:
... to use the power LED as a "General Morse Code Display" as a primitive form of visual interface, so it can be used for small short "messages"...

for turning LED steady on:
echo 'default-on' > /sys/class/leds/nanopi:blue:status/trigger

for turning LED off:
echo 'none' > /sys/class/leds/nanopi:blue:status/trigger

between you should use the sleep command with
sleep 1
for a long light

or
sleep 0.5
for a short light

you also need a pause between every light-pulse

OK, lets build some simple "proof of concept" scripts to explore the idea, also a small presentation slide showing the reason that why it may be a cool idea... and upload it to github, so that others can see the benefits (if any) and adapt for other SBC...

Title update: SBC O-LED (SBC One Led Display Interface)...

Even if is necessary to connect a LED to GPIO, the mechanism, I believe, can be interesting...

There are also, low cost piezzo speakers that can be used (on GPIO) to sound the Morse Code, so using the same scripts...

Regards,
Valter

About the ONBOARD LED MORSE CODE display idea...

A very simple demo/tutorial sample code is here:
https://github.com/t2age/sbc-moled



Tested on NanoPI NEO and RaspberryPI 3...

Should work on ANY SBC, provided that you change the 2 lines for "on" and "off" of the LED...

For onboard LEDs and also for GPIO... should be easy to adapt...

Below picture is the "why" I believe that even Morse Code and ONE LED can be helpful...



For very simple messages, 1 LED should be interesting enough...

Regards,
Valter