Raspberry Pi Stack Exchange
Raspberry Pi Stack Exchange

Questions tagged [led]

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

The onboard LEDs of the Pi (depending on the model): POWER, OK, FDX, LNK and 10M are discussed at How do I control the system LEDs using my software?

471 questions
43
votes
5 answers

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
35
votes
1 answer

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 two embedded in the Ethernet port, and two on the…
PythonNut
  • 566
  • 1
  • 6
  • 12
14
votes
4 answers

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 have a small stockpile of the RGB's. I know for…
atrueresistance
  • 203
  • 1
  • 2
  • 10
7
votes
5 answers

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. (default "mmc") But are there other…
Lucas Walter
  • 175
  • 1
  • 1
  • 6
7
votes
5 answers

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 without any hassle in any programming language…
JustAMartin
  • 251
  • 1
  • 3
  • 9
7
votes
4 answers

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 too much? Because 20+20+20=60, so its more than…
tecmen
  • 71
  • 1
  • 1
  • 2
5
votes
3 answers

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 around and there's lots of led strips, but I need…
stu
  • 153
  • 5
4
votes
3 answers

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 error but there is no effect on the LED when I use…
Chen Zhenhao
  • 43
  • 1
  • 1
  • 3
4
votes
1 answer

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 currently turns on as soon as there is power to the…
Catfish
  • 193
  • 8
4
votes
1 answer

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 Raspberry pi). What kind of equipment and chips do I need…
Matthew
  • 221
  • 1
  • 2
  • 4
3
votes
1 answer

Big LED matrix controlled by Raspberry Pi

It is possible to attach simple, monochrome Nokia Cell Phone display to rpi and it displays whole graphics to it. So is it possible to do the same with custom LED matrix (I mean like 41*15 or more pixels, preferably RGB LEDs)? I'm thinking of sth…
Marian Paździoch
  • 209
  • 2
  • 12
3
votes
2 answers

WS2801 LED's only glow white

FOUND THE PROBLEM: apparently my Raspberry is somehow broken because it does work on the raspberry from someone else... I bought the raspberry and a strand of ws2801 led pixels and I try to make them light. The only thing they do is glow white (all…
CodingCindy
  • 41
  • 7
2
votes
3 answers

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. Do you know any boards available for this purpose…
Sci00213
  • 49
  • 1
  • 4
2
votes
0 answers

SenseHat; Random Pattern using FrameBuffer: No Error?

This Raspberry Pi Post talking about the SenseHat gives the following example to fill up the LED matrix with random colours: cat /dev/urandom > /dev/fb1 This works: but also generates the following error: cat: write error: File too large I can use…
monojohnny
  • 569
  • 1
  • 6
  • 17
2
votes
1 answer

Why are my LED colors in GRB and not RGB?

I'm using a Pi to drive a Fadecandy board to light up a varying-length string of RGB LEDs in different, pulsating colors. I've been successful, however one snag I ran into along the way was programmatically defining the LED colors in RGB. I copied…
Ryan Schuster
  • 125
  • 1
  • 6
1
2 3