Configuring LED Indicators on Orange Pi Zero 3

 

Configuring LED Indicators on Orange Pi Zero 3

There are two indicators on the Orange Pi Zero 3: a red and a green LED. They are quite bright. While the red indicator only blinks occasionally, the green one stays on constantly after Linux boots. This doesn’t suit me, so I decided to find a way how to configure them.

The first thing to do is check the available triggers and determine which one is active. This can be done using the following commands (shoulbe be executed as root):

# cat /sys/class/leds/red:status/trigger

none usb-gadget usb-host 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 disk-activity disk-read disk-write mtd nand-disk [heartbeat] cpu cpu0 cpu1 cpu2 cpu3 activity default-on panic mmc0 mmc1 rfkill-any rfkill-none rfkill0 stmmac-0:01:link stmmac-0:01:1Gbps stmmac-0:01:100Mbps stmmac-0:01:10Mbps rfkill1 bluetooth-power hci0-power rfkill2

# cat /sys/class/leds/green:power/trigger

none usb-gadget usb-host 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 disk-activity disk-read disk-write mtd nand-disk heartbeat cpu cpu0 cpu1 cpu2 cpu3 activity [default-on] panic mmc0 mmc1 rfkill-any rfkill-none rfkill0 stmmac-0:01:link stmmac-0:01:1Gbps stmmac-0:01:100Mbps stmmac-0:01:10Mbps rfkill1 bluetooth-power hci0-power rfkill2

The current trigger is enclosed in square brackets […]. For the green LED, the “default-on” condition is selected, meaning it will always stay on.

To change the condition, you need to write the desired trigger name into the same file. For example, if I want the green LED to blink only when accessing the MicroSD card:

# echo “mmc0” > /sys/class/leds/green:power/trigger

Depending on the distribution, there are different ways to set this command to run at system startup. I am using Armbian, and it seems to automatically remember the state and restore it after reboot. Therefore, there was no need to add this command manually.

Comments

Post a Comment

Popular posts from this blog

How to use SPIFFS for ESP32 with Platform.IO

Image
One of my pet projects is a controllable power supply based on the ESP32 with a web interface (GitHub repository: https://github.com/vshcryabets/Esp32AdjPsu ). Previously, I created simple web pages directly in the code using C++. However, in this project, I realized that working this way is not usable — I should separate the firmware code from the web application code. Most often, the SPI Flash File System (SPIFFS) is used for this (official documentation here - https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-reference/storage/spiffs.html ). SPIFFS allows to store data as separate files that can be both read and written. What is the size of SPIFFS? Let’s take a look at the typical flash memory layout in the case of a 4 MB flash ( https://github.com/espressif/arduino-esp32/blob/master/tools/partitions/default.csv ): # Name, Type, SubType, Offset, Size, Flags nvs, data, nvs, 0x9000, 0x5000, otadata, data, ota, 0xe000, 0x2000, app0, app, ota_0, ...
Read more

ESP8266 module with OLED screen (HW-364A)

Image
I received a few of these modules. They come with the older ESP8266. No problem, there’s always a use for it. A major plus is that the module has a built-in 0.91” 128x64 pixel OLED screen, which is connected via an SSD1306 controller. You can also find ESP32s with OLEDs, though they are pricier. Out of the box, the test firmware demonstrated its OLED display working perfectly. But when I tried the samples from the seller, I just got a black screen. According to the documentation, the display is connected via software I2C with SDA on D6 and SCL on D5. However, when I uploaded a test project with these specified display settings, I got nothing. No signs of life on screen. I started looking for something similar and found many analogous modules from Wemos or with the ESP32. But they all had completely different I2C display connections. At some moment, while trying different libraries for the SSD1306, I made a mistake in the configuration. I set the pins in reverse: SDA - D5, SCL - D...
Read more