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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.

-2
votes
2answers
353 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
297 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
203 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
121 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
4k 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 ...