Stack Overflow
Stack Overflow

Questions tagged [led]

A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices.

A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices, like mobile phones or micro-controller boards.

733 questions
4
votes
2 answers

A delay of a Few seconds when trying to power on Led flash

Im trying to power on the led flash, but the led flash powers on after a delay of a few seconds. I have a built in torch in my phone, and when I click it it the flash turns on immediately. Whats the problem here? Heres my code: private void…
Npv23g
  • 726
  • 9
  • 32
4
votes
1 answer

Android: LED doesn't turn on/off

I'm trying to write a little Android widget with a button that turns the camera flashlight on/off. I know, there a thousands of it out there, but I want to learn Android (and little steps seem to be the best way). Now I've read the official…
roecket
  • 41
  • 2
4
votes
1 answer

How can I switch On / Off LED Camera Flash on Windows 8 tablets (such as ATIV Smart PC)

I can't find a code to control windows 8 tablets camera flash. Can anyone help me get it?
Abdulla Eqab
  • 51
  • 1
  • 5
4
votes
2 answers

LEDs supported on the android device

Is there a way to know the number of LEDs an android device supports . For eg certain device support notification and charging LEDs and some devices support only charging LEDs . Is there a way for an app to know the number of LEDs present in the…
sim
  • 239
  • 7
  • 17
4
votes
1 answer

Arduino sketch does not work, the pins do not output anything

I have an Arduino Uno, and I'm trying to control my s107g rc helicopter with it. This code was available for download along with a few Youtube videos showing tests of it. So when I tried it with the IR led it didn't work. I tested it with normal…
Matthew Brand
  • 83
  • 7
4
votes
1 answer

LED Matrix using AVR Controller

I have created a 8x8 LED Matrix that is controlled by a mircocontroller (specifically Atmega8), an 8-bit shift register (HEF4794), and a driver array (MIC2981). The problem I having is that the pattern that is supposed to be displayed is not…
Scott Gardner
  • 41
  • 1
  • 2
3
votes
3 answers

Arduino RGB LED Clear

I have an RGB LED and have pins to 9, 10, 11 and a pin to ground. Resistors have been provided for R, G, and B. When I do: analogWrite(r, 255); // I see a red color analogWrite(g, 0); analogWrite(b, 0); analogWrite(r, 0); analogWrite(g,…
August
  • 2,408
  • 9
  • 49
  • 85
3
votes
1 answer

Weird output for RGB

I am trying to manage some LED strips with my mobile device using bluetooth + Adafruit NeoPixel. I almost had the sketch finished but I have found the numbers for RGB are not appearing as I expected and I cannot find what I am doing wrong. Imagine…
UnitedFioreMages
  • 35
  • 4
3
votes
9 answers

How to hook up LED lights in C++ without microcontroller?

I want to light up/off LEDs without a microcontroller. I'm looking to control the LEDs by writing a C++ program. but the problem im having is hooking them up is there a free way to do !!!! I'm using Windows XP if that is relevant. I have LEDs but I…
H4cKL0rD
  • 4,775
  • 15
  • 47
  • 72
3
votes
2 answers

How do I detect if my iOS device has an LED light or not?

How do I detect if my iOS device has an LED light or not? I am trying to see the difference between an iPad 2 (front and back camera) and an iPhone 4 (front, back + LED light)
Ethan Allen
  • 13,099
  • 22
  • 89
  • 175
3
votes
1 answer

Control LED brightness by using MCP3002 Analog to Digital Converter

I'm trying to control a list of PWMLED brightness by using MCP3002 ADC and Potentiometer. My issue is when I run my script everything is functioning as expected, except the potentiometer that is connected to MCP3002 ADC, it won't adjust the…
MrYosuko
  • 47
  • 7
3
votes
2 answers

dumb question: Is there a way to make a color pattern repeat every X number of LEDs? Or do I have to write out the pattern for each LED in the strip?

I have a strip of 288 addressable LEDs and it is broken up into segments of 12 LEDs each. I have already written a bunch of code for colors and patterns designed for just one segment. The single colors were easy enough to adjust to fill all of the…
Z B
  • 43
  • 3
3
votes
1 answer

How can I make an LED blink every n seconds without developing a lag?

I'm using an Arduino Uno to control LED. I want the LED to turn on every m seconds and remain ON for n seconds. I've tried this code using the delay() function (by adding delays after LED is turned ON and OFF) and also using the millis() function…
Severus
  • 131
  • 4
3
votes
1 answer

Turn on vibration on Android by terminal command

Since long I am modifying Android kernels, but now I am stuck to find prompt while starting the Android. I am adding recovery inside the kernel image. For this there will be a prompt like vibration, LED or flash light for entering the recovery as…
Abuzar Shaheen
  • 43
  • 1
  • 8
3
votes
5 answers

USB drive LED flash

I was recently reading about the Arduino's Hello World application, and I thought to myself, "I wonder if I can do that with hardware that I have right now." Since I don't have an Arduino, I grabbed a usb flash drive that I had laying around and…
troyal
  • 2,339
  • 6
  • 22
  • 28
1 2
3
…
48 49