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Questions tagged [led]

An LED is a type of light source which is typically fairly small and has low power requirements.

7
votes
3answers
5k views

Multiple independent LED patterns

I have an problem, which at first thoughts (and being new to Arduino) I though was a perfect application for an Arduino. However, after trying and failing to implement it I am doubting myself! Simply ...
4
votes
1answer
905 views

Reading button presses with the 74HC4067E multiplexer

My project is progressing quite well, but I am having some issues reading button presses through my MUX. The Goal Cycle through twelve buttons and twelve LEDs. When a button is pressed, light up the ...
2
votes
1answer
62 views

Issues with a basic circuit

I am having some issues with a simple circuit. I would expect this circuit to light up this LED constantly when the Arduino is plugged in. I have the Blink tutorial sketch loaded, but I don't think ...
2
votes
1answer
150 views

Confusion around LEDs on a breadboard

I am just starting out with an Arduino Diecimila and am playing around with LEDs, and am confused by why some circuits result in an LED not lighting up. Successful Scenarios: Yellow LED from pin13 ...
3
votes
3answers
2k views

Arduino PWM fading led

I am trying to blink an LED with PWM on Arduino. I don't know what is wrong but my LED is not fading as expected. What is wrong? I think that I have bad registers settings, but I am not sure. LED ...
4
votes
2answers
8k views

Receiving SMS by Arduino GSM Shield and control the LED with the content of this SMS?

I am using Arduino GSM Shield receiving SMS from an Android app. And the content of this SMS will control a LED. If the content of this SMS is not "off", the LED will be on and the content will be ...
1
vote
1answer
639 views

Executing multiple functions/commands on Arduino

I am using an RFduino and an iOS application to control some RGB LEDs. This is how I'm sending a string command to the module: - (IBAction)fadeButtonPressed:(id)sender { [rfduino send:[@"fade" ...
-2
votes
2answers
367 views

controlling LEDs, few pin outputs lots of LEDs

We need to control many leds, about 40 with arduino (UNO) and we need some remain turned on and other off at the same time. Muted or pinned vary constantly. What should I use to do this, I have ...
2
votes
1answer
236 views

Initialize a “Matrix” object in my own library?

So, I'm trying to make a custom library to drive a 8x8 Bi-Color LED Matrix from 2 MAX7219's that incorporates two "Matrix" objects from the "Matrix" library and I cannot, for the life of me, figure ...
2
votes
1answer
302 views

Animated LED Strip & Sensing an Object

Problem: Have an LED strip do some animation (say it takes 15 seconds for that line of code to run) meanwhile, have a sensor (tried methods: PIR sensor and ultrasonic sensor) watching to see if an ...
3
votes
1answer
206 views

8-segmet LED's on Adafruit Trinket

I would like to have an array of eight 7- and 8-segment LED numerical displays on my Adafruit Trinket. I know that there are some prebuilt arrays of 4 LED's. So 2 in array would do just fine. However, ...
6
votes
2answers
2k views

Use Higher Resistance Than Instructed in a Circuit

I'm following the "Get Started with Arduino" Guidebook, and I'm at the part where pulse width modulation (PWM) is discussed. The instructions say to create a simple circuit with a breadboard, red ...
0
votes
3answers
1k views

LED Cube lighting wrong LEDs randomly

So I built my First LED Cube and the thing turns ON!!! Pretty happy about that but here is my problem. When I try and get the Cube to display say a basic "outline" (a wire form of a cube only the ...
1
vote
1answer
68 views

Simple Script controlled by Raspberry not working

I can't figure out why the next script is not working. I have attached the Arduino to one USB port of the raspberry pi, in which I've installed pyserial. I just want to turn off/on a led depending of ...
0
votes
3answers
3k views

Why does my wired button always read HIGH?

I have made a simple Arduino program that uses a potentiometer to dim a LED. This program also makes a second LED blink. Finally, I have added a button that controls a third LED; this part of my ...
6
votes
1answer
123 views

LEDs on TX/RX lines interfering with the programmig of the device

I have recently designed a shield to my Arduino Duemilanove, which has 8 LEDs, on the digital GPIO, from 0 to 7, but it won't program with the shield on because the voltage drop is too much on the RX ...
1
vote
3answers
3k views

Program stops working after a minute

I have made this small program to lighten up in sequence 8 LEDs, it starts fine, but it stops working after a minute or so and the first 2 LEDs stay permanently ON, its like the chip stoped, here is ...
6
votes
1answer
3k views

Digital RGB LED animation

I've been trying to get colours fade into each other for a project I'm working on. I have achieved this with the rainbow effect that some from Adafruit's example code, however I want to be able to ...
2
votes
2answers
4k views

Arduino LED matrix and 2D array, data seems to be corrupting

Duplicate of this question I'm trying to drive an 8x8 LED matrix with an arduino nano, but I can't get the LEDs to display what I tell it to. I'm using this LED Matrix Here's my code: int row1 = 2;...
23
votes
3answers
5k views

What happens to the Arduino if you don't use a resistor with an LED?

Making a blinking light seems to be one of the most common beginner projects with Arduino. A typical approach is to connect an LED + resistor (in series) to an IO pin, and connect the other end to ...