Questions tagged [led]
An LED, a light emitting diode, is a light source often used as an indicator.
462
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WiringPi can only turn on 8 LEDs
On my RPi 3 I have a PHP website to control 10 LEDs. Each is wired to a separate GPIO pin and 220 ohm resistor.
Here is the code:
<html>
<head>
<title>LED Control</title>...
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1
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Detecting Button Press and Lighting LED [closed]
Using the pigpio library, I wanted to detect when a button is pressed and turn on/off an LED. I am trying to use the gpioSetAlertFunc function to trigger the LED when the button is detected as pressed....
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How many MAX7219 8x8 can a Raspberry Pi 3 power?
I'm trying to figure out how many MAX7219 8x8 LED matrix can a Raspberry Pi 3 handle without the need of external power.
I would like to connect an array of 8 but I suspect I'll need an external ...
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Trouble with basic blinking LED circuit with attached circuit and python code
Can you take a look at the attached circuit and code (below). It seems the green LED should blink but I'm not getting it to light up at all. Thoughts? Thanks so much!
Circuit:
Python code:
import ...
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2
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Can't turn on LEDs through terminal with PWM
I wrote a crappy Python script that should turn on LEDs connected to the GPIO interface.
import RPi.GPIO as GPIO
import time, sys, json
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
gpioPorts = [...
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1
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Connecting 2 LEDs to a Pi directly without using a breadboard
I'm planning to connect 2 LEDs directly to my Pi 3's GPIO pins using only the LEDs and a 330 Ohm resistor. Can I accomplish this task without damaging my Pi?
I don't want to use a breadboard or any ...
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1
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help reconstructing blinking LED circuit that required GPIO #17 pin low rather than high
I am working through a series of lessons on using the Raspberry Pi 3 Model B with the Osoyoo Raspberry Pi Starter Kit. The first lesson is to build a simple circuit in which GPIO #17 is used to power ...
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Running Flask on Pi Zero getting uneven PWMLED
This is my first trial run using a Raspberry Pi Zero W to run RGB LEDs following this tutorial: https://dordnung.de/raspberrypi-ledstrip/
I've completed the tutorial, have everything wired up, and ...
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1
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RuntimeError: No access to /dev/mem
I'm using the PXfmini with the raspberrypi3 for a project and I need to use mavros and python code.
My operative system is Frambuesa.
I created the catkin workspace and I tested the c++ file ...
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3
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How complicated is it to light an LED?
I have been trying to right my first physical script, to simply light an LED. I HAVE BEEN DOING HOBBY ELECTRONICS FOR A WHILE, and lighting an LED is simple.
Wanted to use Pi to light LED, but I can'...
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Very simple flashing 8-LED ring and button on Raspberry Pi 3
This is my first Raspberry Pi project that involves an LED ring with button control, and I have some very basic questions.
I am making a halloween costume with a Raspberry Pi and this SparkFun ...
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3
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Basic questions about inputs/outputs on a breadboard (Pi 3)
I have started my first basic project today and I have a few questions I couldn't find answers to yet or I just don't know how to search for any. Sorry if those questions seem a bit stupid, but I will ...
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Why optocoupler (4N35) needs resistor?
I am learning how optocoupler works. Now I am passing Lesson 8 4N35
I've found why resistor needed for LEDs, but why there is need for resistor between optocoupler and power supply/input pin?
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I accidentally shorted my RPi and now none of the GPIOs work, is it fixable?
I have a Raspberry Pi 3 Model B, and while messing around with a breadboard earlier, I took out a jumper from the breadboard that was connected to the 5V power pin on the RPi and the jumper slipped ...
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1
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LEDs won't follow pattern (voltage issue?) with Pi 3
First and foremost, let me say that I'm new to electronics and the Raspberry Pi. I'm a programmer. I have never done this type of project before.
Now, I have a Raspberry Pi 3 model B that controls my ...
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0
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Lighting Issue On Snapshots
I'm creating a proof of concept project for my Pi 3. The concept is to take a photo using a USB webcam when a button is pressed. That part was simple using OpenCV. However, the lighting is fairly ...
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Use a single GPIO pin to activate both LED and buzzer
Is this possible? My question yesterday led me to this circuit using an NPN transistor for the buzzer: https://elinux.org/RPi_GPIO_Interface_Circuits#Output_circuits
It's actually more like this: ...
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1
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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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1
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GPIO pin wiring for LEDs and their resistors
I have a Raspberry Pi 1 Model A and am trying to control an LED from an app that I will be running on it. The wiring I'm planning on going with is:
Even though thats a RPI 3 in the diagram above, the ...
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2
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Why won't the LED turn on?
Here is the code I am running on the Pi through IDLE.
import RPi.GPIO as GPIO
import time
GPIO.cleanup()
GPIO.setmode(GPIO.BOARD)
GPIO.setup(12, GPIO.OUT)
for i in range(50):
GPIO.output(12, 0)
...
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Why GPIO 9 and 10 Cannot Light LED? MOSI and MISO
I have 8 RGB LEDs in a Row. Each RGB LED has 3 GPIO pin to control the color Red Green and Blue. I used all available GPIO pins. I works for the 7 RGB LEDs. One LEDs does not light properly for 2 ...
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Button isn't triggering in python script
Software guy here, first time doing hardware.
Here is my breadboard setup (yellow is GPIO-8, green is ground):
Here is my Python:
import RPi.GPIO as GPIO
from time import sleep
GPIO.setmode(GPIO....
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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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How can I get my raspberry pi 3 to work with SK6812 LEDs without a screen?
I have a raspberry pi 3 and am trying to get it to run the SK6812 LEDs with no screen. When I have my ASUS monitor connected, the LEDs work fine, and when I disconnect the screen and reboot, the LEDs ...
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All the ports are not working of my Raspberry Pi 3 (4 USB port and ethernet port)
According to my knowledge, in my circuit only power light of Raspberry Pi is working but all other component such as USB port and Ethernet port is not working. Please help me......
I have just bought ...
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Failing to turn on a LED with GPIO Pins (Raspberry Pi 3 B V1.2)
I'm trying to play around with my RaspberryPi a bit and I'm failing miserably... ANY help ist highly appreciated!
I'm on a brand new installation of Raspbian, after "apt-get update && apt-get ...
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3
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How to choose appropriate transistor and resistor values for the 4 digit display?
I bought this 4 digit led display
I'm looking at this tutorial and I don't understand why he used such big resistor for his circuit.
Excerpt:
Please note that the pinouts of LED displays vary ...
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Can I control 5050 RGB Strips with the Raspberry pi?
I have purchased 5 meters of a 5050 RGB Strip yesterday. I bought it for my PC case, but of course I don't want to use 5 meters in my case.
I want to do some smart lighting in my room and a bias ...
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Red led on and nothing happens RPi3
I have problem with Raspberry Pi-3.
When I plug on power cable led lights with red and nothing heppens.
I see wrong element on the board.
What is the element?
Сould this be the cause of the ...
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5
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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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2
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Python code with pigpio doesn't work properly
So, I was wondering if I could light up an led a little bit, so the led wasn't neither off, or completely on.
The only way I found on Google to do that was with pigpio, so I installed the program on ...
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Best way to facilitate Pi to Pi communication with no network?
I have written two python scripts. One which drives an LED matrix and displays a message based on which argument(digits 0-5) you pass when you call the script. The script parses the number and selects ...
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Voltage and Current for the Pi [closed]
There's a heap of these questions, so before you mark mine as duplicate I'll try and explain how mine is different.
I don't really know too much about voltage and current, wattage, resistance or ohms....
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Wiring diagram for pair of IR LEDS, P2N2222 transistor
I've tried to imitate the below diagram for my Raspberry Pi using GPIO 0, without a receiver.
The diagram seems to show a resistor going to ground, and an (emitter?) going to ground as well. I know ...
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1
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Need help with Python code
I hadn't programmed on my RPi for a couple of months due to me focusing mainly on my education. Yesterday, finally the school year ended, and so I decided to start programming on my Pi again from the ...
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Pi 3 extend the green status led
Can I extend the green led on the pi 3 by soldering wire and led from the same spot or do I still need to add a diode or something? Sorry for the noob question
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Can't get my LED to flash
I'm trying to get started with GPIO, but I just can't get this LED to flash on and off, for some reason.
I'm using Raspbian on an old model B Pi with a 26 pin breakout board and a breadboard. The ...
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Leave PWM on after executing script?
I made a python script to control a LED strip connected to my Raspberry, the script receives an argument trhough the command line,and uses that argument to control the intensity of the light using PWM....
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Python: How to control a delay switch with timer while script keeps running [duplicate]
I am trying to set up a circuit that will operate my water-boiler through a push-button.
The result i am looking to achieve is:
While Boiler is off:
Button Press: Turn boiler ON, then turn OFF after ...
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Using led screen of a mobile phone on raspberry pi [closed]
I have an old led panel (ONLY) from my old phone. I was thinking about the way to connect it to my raspberry pi 3 and use it as its screen. Is it possible? If i could, what should i do. Thank you all ...
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2
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Python - One momentary switch, LED, and a shut-off timer
I'm working on programming a LED strip lights application that is activated with a momentary push button and if the lights are not turned off by the push button, then they automatically turn off after ...
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I can't find the file "font5x5.py"
I have a serious problem, I've intalled this But in my RPi, I can't find and edit the "font5x5.py". But when I import it with another script, it work. Can you please help a french beginer ??
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Raspberry Pi 3 - GPIO Input not working
I have some experience with Arduino but I'm a complete newbie around RPi. I bought a RPi 3 for my thesis case study and recently I've been trying to get the GPIO to work. The output works fine, but I ...
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2
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My GPIO wouldn't start at the same time
When I run this code below, the 2 LED's do not start at the same time.
The yellow one starts slightly late. (about less than 0.1 second)
Is there something wrong with my code or any suggestions to ...
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After power on Rpi3 RED led steady but green continuously blinking. what could be the problem?
i brought new Rpi3 and boot 16gb card with 2017-03-02-raspbian-jessie when power on red led steady and green blinking is there any problem in booting process of pi? HDMI not showing anything neither ...
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Rasberry Pi LED GPIO using Python
In my project I invoke a python script via node.js on my Rapberrypi B+
model and what the python script does is that it turns on the BCM
GPIO ports as per the python arguments passed through the ...
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2
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Whack a Mole Game
I'm trying to program a Whack a mole game using four LEDS with four corresponding buttons, but I'm getting stuck with how to make one random LED turn on at a time. Here's the code I have so far:
...
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2
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2k
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LED on breadboard lights up on boot
I have a setup like below:
The script is supposed to turn the led on, sleep and turn it off again. And the script does work.
import RPi.GPIO as GPIO
import time
# This script will turn on the LED ...
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1
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How to control LEDs connected to the raspberry pi via I²C
I want to control a lot of LEDs (120 LEDs for example) independently of each other using the Raspberry Pi model B+, but the number of GPIO pins in the Raspberry Pi is not enough. So I thought of using ...
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2
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How to run a LED sequence while button is pressed?
I have a function PlaySequence() which plays a sequence of 'LED on' and 'LED off'. There are two LEDs and the times when each LED must be on or off are defined. The function may look like this, but ...
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