Questions tagged [led]
An LED, a light emitting diode, is a light source often used as an indicator.
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How do I control the system LEDs using my software?
There are 5 LEDs on the RPi: OK, PWR, FDX, LNK, 10M.
I'd like to know if it's possible to control any of these from software i.e. turn them on, or change intensity (or even change colour gasp).
And ...
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What do system LEDs signify?
There are 5 status LEDs on the Raspberry Pi board. While I can guess what the POWER LED signifies (the power being attached), I am not sure about other four.
So, what do OK, FDX, LNK and 10M signify?
user13
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Why is a resistor needed for LEDs?
While looking for a basic task to get familiar with the Raspberry Pi and its GPIO pins, I decided that driving an LED sounded simple enough.
While investigating how to go about this task I've noticed ...
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What do the LEDs on the B+ mean?
Not a duplicate of this RPi.SE question, as I'll explain in a moment. GPIO.RPI_REVISION returns 3.
As far as I can tell, looking at my B+, there are no LEDs labeled: OK, FDX, LNK or 10M. There are ...
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Why are some GPIO pins HIGH when the Raspberry Pi boots up?
I have an easy circuit wired up, with an LED connected to pin 18 on the BOARD reference. I run a simple program to put pin 18 to HIGH, which turns the LED on, and then a couple of seconds later, I set ...
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Wiring RGB LED's
I was wondering if it is possible to connect 8 individual RGB led's much like the adafruit strip. I saw the Pumpkin Pi project and would like to build one. I don't have any yellow or red LED's, but ...
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What do I need to simulate traffic lights using LEDs?
So I'm making a model that simulates traffic lights (Red, Amber, Green) so there will be three LEDS that need to be preferably extendable (I don't want them attached directly to the breadboard) but I ...
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Disable LEDs Pi Zero
Can I disable the yellow (PWR?) LED on the Pi Zero?
I've tried setting the brightness to 0 of led1 (it starts life as 255) and led0 is already 0 but I still get the LED glow.
Out of interest, I only ...
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Controlling many LEDs with few GPIO pins
I successfully completed my hardware "hello world" using this guide:
http://www.raspberrypi-spy.co.uk/2012/06/control-led-using-gpio-output-pin/
Now I'd like to move on to bigger and brighter things,...
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How can I turn the lights off on my pi?
I'd like to build a small internet radio out of my pi, but I'd like to use it at night, when the flashing LEDs would be disturbing. Is there any way to disable them?
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What's the Difference between Raspberry Pi and Arduino?
This question stems from a large lack of understanding, but it concerns a project I've wanted to do for a while.
This is an Instructables page for an 8x8x8 led cube, and the 70th step addresses the ...
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Visual/audio status/activity indicators
What, if any, indicators of system status or activity are available on the Pi?
Audio - I'm talking about a beep when it's turned off, or a series of beeps indicating POST information, etc.
Video - ...
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Controlling 400 LEDs from a raspberry pi
I have a client who has several large bronze signboards, each with 100-150 little light bulbs on it, totaling approximately 400 bulbs. The bulbs are turned on and off on a schedule, currently by hand ...
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Is there any built in LED connected with GPIO pin?
In Arduino a built in LED is attached with number 13 Digital pin.
Is there any LED like Arduino in Raspberry Pi,which I can use to test my code?
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How to blink LEDs on/off continually, while continuing execution of a script?
I've connected red and green leds via GPIO and I can successfully switch them on/off using RPi.GPIO - now I'd like to:
start an led blinking on/off every 1 second
have the script continue its ...
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Are there other act_led_trigger options besides "mmc" and "heartbeat"?
/boot/overlays/README has this text:
act_led_trigger Choose which activity the LED tracks.
Use "heartbeat" for a nice load indicator.
...
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Which addressable RGB LED strips are beginner friendly and Raspberry Pi friendly?
I'm programmer and my electronics knowledge and soldering skills are pretty basic.
I want to find a bright, addressable (a.k.a. digital) RGB LED strip which can be attached to RPi and programmed ...
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Using jumper cables to turn on LEDs
Currently I have my LED's anode connected to the GPIO pin that controls it and the cathode is attached to a resistor and the other end of the resistor is on my breadboards - rail. How can I use jumper ...
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Raspberry Pi LED current limit
I've got an Raspberry Pi and I want to control some LEDs. I've read that the maximum current at the GPIO pins should be less than 50mA. But each LED uses 20mA. Does that mean that even three LEDs are ...
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Is my Pi's GPIO damaged?
I am trying to test GPIO output on a Raspberry Pi, and I am wondering if it is broken.
These setups work:
3v3 >> +LED terminal -LED terminal >> resistor >> GND (the LED is
unusually dim here)
3v3 >>...
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Why does sudo not work in this case?
I was playing with the raspberry pi leds (How do I control the system LEDs using my software?)
Interestingly, on my pi the following command fails:
sudo echo heartbeat >/sys/class/leds/led0/...
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Connecting blue LED (3.3V)
I've recently started doing basic diode connections (red and green diodes). I've also got blue diodes, but there's one thing that prevented me from connecting them already, namely - the specs say they'...
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2nd LED not working when connected to different GPIO port
I am trying to make 2 LEDs flash but I have connected both to different GPIO ports. Both LEDs are being used with a 220 Ohm resistor.
my red LED is connected to GPIO4 (Pin #7) while its ground is ...
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Using one Raspi to control long (>100ft) of 5V LED strip
I am using the below LED strip for accent lighting
5M WS2801 Blcak PCB 32LED 5050 RGB Digital LED Strip Individually Addressable 5V
item: nonwaterproof black pcb ws2801 led strips
Model: 5050RGB ...
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What is the maximum number of RGB LEDs that can be controlled individually?
I've read that 17 LEDs can be controlled individually with the 17 GPIO pins.
Does that mean that only 5 (17 / 3 = 5.6) RGB LEDs can be controlled with one Pi?
Would it be possible to individually ...
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Is there an addressable LED product that I can wire to a Raspberry Pi where all the LEDs are separate?
I have a RPi project where I want to build but alas I'm a programmer, not an electrical engineer. I can solder things, but I couldn't tell you what resistor I needed to put where.
Anyway, I looked ...
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How to indicate read / write disk operiation via LEDs connected to GPIO
I think I know how to connect LEDs to GPIO but I want to illuminate them when there is read / write operation to sdcard or other mass storage connected to Pi/ Is it possible ? I am doing little ...
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I need to control 8 LED's but I can only control 3? [helpful pictures attached]
I'm very new to electronics in general, but I want to build a small project where I can individually control (from a GPIO pin) 8 LED's. From what I understand, each GPIO pin on the Pi (Pi2 model B V1....
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How to use 2 x MCP23017?
I need to control 32 L.E.D's individually, now looking through the forum, the common solution is to use MCP23017 chips, as they can control 16 l.e.d's. With that in mind, I would require two chips.
...
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Board sign from LED strips
I'm trying to build a sign board made of LED strips, just like this
I found a ton of examples on controlling a single strip and also examples using the adafruit premade led boards (16x32), but no ...
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Is it possible to connect an LED directly to the GPIO of the Pi?
I was wondering if it is possible to connect an LED directly to one of the GPIO pins of the Pi? The reason I ask is that, I have read from many sources that if I am not using some sort of break out ...
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Why can't I turn on an LED through Python?
I have an LED connected to pin 11 on the Raspberry Pi header, (also known as BCM/GPIO pin 17, and GPIO0). I have installed the Raspberry Pi Python library according to these instructions.
Attempt 1
...
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Pi Zero W - Switching camera LED from program or command line
So far failing to switch the camera LED either from Python using RPi.GPIO or from the command line using /sysfs/gpio... I've tried using both GPIO5 and GPIO32 as suggested from various online sources,...
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GPIO stuck in High Mode
I'm new to this whole RP world, and I'm trying to learn it.
I've been trying to follow this post, and connected my Pi this image below
Connection between Pi and Adafruit T-Cobbler Plus
Wiring
...
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Powering WS2812B LED strip from Pi brownouts
I have a Raspberry Pi 3 Model B currently controlling and powering a strip of WS2812B LED's. A separate 5V 15A power supply powers the Pi through pins 2 and 6, while the LED's are powered off of pins ...
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How to calculate how many watts a resistor need?
I want to build the most simple circuit that connects my pi, the resistor and a LED. I looked up resistors but there are so many resistors 0.1W, 0.125, 0.25, 0.5, 1W, 2W ,3W etc... Which one do I ...
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Control WS2801 with Raspberry Pi
Anyone has managed to get raspberry pi connected to WS2801 RGB Led Strip?
I have followed the connections here at adafruit: and tried to test the LED with pixelpi.py.
The pixelpi.py runs without ...
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Control 5m of WS2812 LED Strip: Wire it up
I want to control 5m of WS2812 LED Strip with my Raspberry Pi, which will be placed around two Ikea Billy shelves. I read some articles and tutorials regarding this topic:
http://popoklopsi.github....
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Can't get LED to turn off
I'm a rookie with Raspberry Pi and electronics in general. I was able to get my LED to turn on when I plug it into the breadboard but i'm unable to get it to respond via Python or wiringPi. The LED ...
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Powering and controlling hundreds of LEDs with a Raspberry pi
How do you utilize the Raspberry PI to be able to power hundreds of LED lights?
Imagine I have Christmas Lights (LED) and I want to be able to control all individually (write a program on the ...
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RGB LED is not lighting up
I connected an RGB LED(common anode) via the GPIO, and tried to get it to light up, but for some reason when I run the command, the LED does not light up. Here's the code I'm using
import RPi.GPIO as ...
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Troubleshoot MCP23017 and LEDs
Anyone have any tips to help troubleshoot turning a simple LED on connected through the MCP23017?
I've installed i2c-tools, and smbus.
Nothing in my blacklist.conf
Added i2c-dev to /etc/modules.
...
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Read status of power led using sysfs
I want to read the status of GPIO35 on a Raspberry Pi 2 Model B using the sysfs on Raspbian with a 4.0.8-v7+ kernel. I can access other GPIO pins using /sys/class/gpio but the two leds are already ...
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Lighting a LED slowly with GPIO
What is a good way to make an LED turn on and off slowly using a Raspberry Pi? Im trying to hook up an led to become a Tardis lamp, but since the Pi doesnt have ADC/DAC, Im kind of stuck. What are ...
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Power LED from 3.3V Power Pin without Resistor
I tried wiring one white LED to the 3.3V pin on a Pi Zero W with a 330 Ohm resistor but it's not as bright as I would like. If I wire it up without a resister I get a good amount of brightness. Is ...
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Why Isn't My Ethernet Working?
I just got Pi Model B. I downloaded Wheezy on SD card and plugged in all of my cords. Everything works fine except the Ethernet port.
The LINK LED flickers for a second while booting up, but then it ...
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Turn off external LEDs on Raspberry Pi 3
I see there are quite a few posts about this already but none seem to work for me.
I am running a pihole server on my RPi 3 and I would like to turn off the external power and LAN LEDs (green and ...
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How to control 12V LED with the GPIO?
Heyo!
How to control single 12V LED using Raspberry's GPIO?
To be more exact, I need to connect 12V LED & push button to Raspberry Pi 3 B+ GPIO in order to control LED (on/off) and read button ...
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Help lighting LED via GPIO pins
So I got an RPi and a canakit, I'm trying to follow a guide to get a simple program to make the LED blink. I have very little experience with RPis so it's probably a very simple error, but I can't ...
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Want to run a simple C program on startup of pi
Im new to linux and the pi . Im stuck with this situation where
Iv been trying to run a simple LED blinking C code as a test , so that it will be executed during startup
Code works fine when its ...
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