Questions tagged [led]

An LED, a light emitting diode, is a light source often used as an indicator.

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votes
5answers
77k views

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?
20
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3answers
28k views

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 ...
70
votes
7answers
57k views

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 ...
12
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2answers
32k views

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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vote
2answers
116 views

Slight dip on the GPIO 5v line when LEDs are on

I have my raspberry pi set up to do two main things: control 16 LEDs via 16 transistors each connected to an out pin. The LEDs are collectively fed the 5V from the GPIO. power a chip also on the 5V ...
10
votes
2answers
4k views

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 ...
2
votes
3answers
53k views

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 ...
5
votes
1answer
6k views

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 >>...
3
votes
3answers
13k views

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 ...
4
votes
1answer
2k views

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 ...
1
vote
2answers
5k views

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 ...
4
votes
1answer
706 views

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 ...
4
votes
1answer
859 views

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 ...
2
votes
3answers
360 views

Powering 100mA LED

I want to power an 1.5V LED fully and control it using pi. I can only use 16mA per pin and i need 100mA. Can you give me suggestions? I can turn it on with 5V and 35 ohm resistor but not control it. ...
2
votes
4answers
3k views

Red LED after `sudo halt`, may I unplug?

I flashed Raspbian and I use my Pi headless, connecting via SSH. To power it off I do sudo halt, which disconnects me from the SSH. After a few green led blips I have steady red led on. Does it mean ...
2
votes
1answer
813 views

LED resistor question

I'm fairly new to electronics and I'm in the process of creating a IR Birdbox using a Pi Zero and IR Camera. I have a quick question regarding the correct usage of Resistors for IR LEDs (Or any LEDs ...
1
vote
1answer
118 views

Issue with a 12v switch via GPIO output

I am a beginner when it comes to electronics so I would appreciate your help with a simple project I am working on and have been struggling with for several days. The idea is that I have a PIR Sensor ...
-1
votes
1answer
244 views

Raspberry Pi and car led ground effects

I am about to add led strips to my car. I will have at least 4 zones to start out and might add more. 1. Under carriage 2. Front end 3. External 4. Internal Doing it now, I will have 4 controllers ...
34
votes
1answer
86k views

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 ...
7
votes
5answers
24k views

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 ...
13
votes
2answers
3k views

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 ...
11
votes
2answers
5k views

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 ...
6
votes
4answers
5k views

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. ...
5
votes
3answers
721 views

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 ...
3
votes
1answer
1k views

Powering up a WS2812 led strip with different power supplies

I have a Pi powered with its own adapter. I bought a 1 meter ws2812 led strip and bought a separate power supply for it (5V 6A). I plan to plug the +5V of the power supply directly to the +5V section ...
1
vote
2answers
200 views

Pi4 GPIO Control with Java

I am basically trying to turn on a led by using pi4j library. My code is pretty simple: public static void main(String args[]) throws InterruptedException { GpioController gpioController = ...
0
votes
2answers
685 views

Resistors on the RPI GPIO

I need to figure out what kind of resistors to get with the GPIO. In total, I have 13 LEDS hooked up to the GPIO. 1 Red 5mm, 20mA, 2.4v 2 Yellow 5mm, 20mA, 2.4v 1 Green, 5mm, 20mA, 2.4v 1 Blue, ...
0
votes
3answers
172 views

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'...
6
votes
3answers
5k views

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'...
5
votes
4answers
2k views

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 ...
4
votes
2answers
3k views

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 ...
4
votes
1answer
817 views

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 ...
4
votes
1answer
8k views

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 ...
3
votes
2answers
1k views

Powering several LEDs from GPIO output

I'm currently working on a "rotating cube" project where a raspberry pi will be used to determine which cube face is at the top and any given time using an accelerometer and light it up with LEDs. So,...
3
votes
3answers
595 views

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 ...
2
votes
1answer
715 views

Model B+ i2c issues with 7 segment display

I purchased a 4 digit 7 segment display from adafruit and got it working on my old model A running adafruit occidentalis operating system. I recently bought a model B+ and installed the latest version ...
2
votes
4answers
3k views

Control 18 LEDs individually? (17 GPIO pins)

Note: I have read Controlling many LEDs with few GPIO pins, but I can't buy additional parts (Degree project) The end result is to make a noughts and crosses grid with 2 LEDs per grid cell. This ...
2
votes
2answers
981 views

AC mains dimmer dimming 7W LED lamp problem (RpiZero + MPDM V4.1)

I'm trying to dim a 7W LED with a Raspberry Pi Zero for home automation. However it doesn't work as expected. I followed this tutorial : https://www.youtube.com/watch?v=wqY4-gHqvZI . I have the exact ...
2
votes
1answer
638 views

Other hardware for camera slots?

I think the raspberry should get more cool hardware like the camera that works with the slot onboard. I'd love to get a fast RS485 onto this slot because i need all my GPIOs for LEDs. Currently I use ...
1
vote
2answers
53 views

Breadboard circuit with LED going through 2 circuits doesn't work as expected

I have the resistor, GPIO24, and the LED anode connected along the same row of a breadboard. The signal from GPIO24 works as expected, but any signal from GPIO23 is lost and the LED will not light. I ...
1
vote
2answers
799 views

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) ...
1
vote
3answers
4k views

'Zoom out' on 3.5 inch LED screen

I bought a 3.5" LED screen that is on my Pi, however it is nearly impossible to use because edges of windows are clipped off etc. How can I 'zoom out' so that all the windows are really tiny? ...
1
vote
3answers
540 views

I'm looking for a serial input type “polychromatic” LED as an output for my raspberry pi. Does such a device exist?

Forgive any potential neologisms, but I would like to acquire a light that can, say, display 64-256 different shades of color based off of a digital numerical input signal? It can be a usb light, but ...
1
vote
1answer
707 views

extend the current for PWM LED Control

i am using the raspberrypi to have 2 led's fade up and off. My script works and its ready to go. But i need to get my LED's brighter. Is there a way to extend the GPIO Current of the rasperry pi ? ...
0
votes
1answer
2k views

What GPIO pins are required to Power RPi? [duplicate]

We are using Raspberry Pi Model B: We used USB connector from PC - confirmed output - 5V, with 2 leads: Connected +5V to Pin 2 Connected GND to Pin 6 on connector - Inserted Ethernet cable ...
0
votes
2answers
975 views

LED strip has R-G-B instead of DI and CI

I went and bought an LED strip which has the following labels +V R G B How does this correspond to another naming scheme I have seen which looks like so: GND DI CI +5V I could use this tutorial, ...
0
votes
1answer
67 views

RFID and LED Script disables RFID reader until reboot

I have two simple scripts, which work individually. One simply lights an LED, the other reads RFID. Now I want to put them together, but seem to fail. Once this runs, I can't read RFID anymore until ...
0
votes
1answer
271 views

Piezo Buzzer Driven By Rpi GPIO Problem

I'm trying to light up an LED and play a buzzer noise at the same time. Here is my code so far: Import RPi.GPIO as GPIO Import time GPIO.setmode(GPIO.BCM) GPIO.setup(7, GPIO.OUT) while True: ...
-3
votes
1answer
1k views

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 ...