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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
1answer
39 views

Data type problem

I have a program I would like to ask:   I use the Bluetooth control LED to light up. In the picture, the serial port window shows r, but the LED does not light up. What went wrong? Ask everyone, thank ...
0
votes
1answer
32 views

Component with controllable resistance from Arduino? [on hold]

I'm new to Arduino and building circuits, and was wondering if there is a type of component, or some other way to do the following task: I want to control the resistance of a circuit from my computer ...
1
vote
1answer
59 views

How do I make the letters on my Arduino LED matrix scroll faster?

////************************************************************************* ////----------------1.开发环境:Arduino IDE or Visual Studio 2010---------------- ////----------------2.使用开发板型号:Arduino UNO ...
-2
votes
1answer
31 views

Using two leds with one push button [closed]

How can I make the code of this project where I will press one time a button, to turn on the first led (and turn off second led) and when other one press to turn on second led (and turn off the first ...
1
vote
0answers
27 views

Sketch for 5 randomly fading leds not working as expected; what could be wrong?

I'm working on a project with a starry sky, based on fiberoptics and 5 leds. The code should work this way: Start on average brightness, then go up or down according to a set of randomly chosen ...
0
votes
1answer
44 views

if/else on digitalRead not executing on 'else' portion

I am a beginner with C++ but used to be good with BASIC (2 decades ago lol). I'm building a peristaltic metered doser that allows you to input desired mL on a 4x4 keypad and then when 'fill' button is ...
0
votes
1answer
19 views

Define preset colors using FastLed library

I'm using an addressable 150 led strip and an Arduino Nano to control it, using FastLed library. I'm tring do create a function turn_on_leds, which gets 4 parameters: 1) delay time for lighting a ...
0
votes
0answers
15 views

How to make an animation with custom WS2812b?

I want to make a diy LED matrix with WS2812b (7x35). I have a difficulty to program the led animation. Is there some kind of program that has easy interface to custom the led display and generate the ...
-1
votes
1answer
50 views

NodeMCU display temperature and control LED from an autorefresh web page

I'm totaly new to Arduino, I'm using ESP2866 NodeMCU and dht22 to display temperature and humidity in a web page, it is autorefresh (using AJAX) and it works perfectly, I wanted to add 2 buttons to it ...
0
votes
1answer
58 views

How to power multiple LEDs with a microcontroller [closed]

I currently have a "tiny" setup and want to put a few (~20-30) 0402 LEDs on a 1:87 scale car. My current setup is an ATtiny85 USB Mini Dev Board powered by a 90mAh 3.7V LiPo battery which is connected ...
-1
votes
2answers
38 views

LED not turning on with following code

LED is not turning on with the following code. Have tried multiple LED's and double checked wiring. What's wrong? Using an uno. int ldr = A1; int ldrVal = ldr; int led = 6; int lvalue = 900; void ...
0
votes
0answers
22 views

WS2812 Matrix colour problem. Power?

I have 8 8x8 WS2812 Matrix LED boards connected together to make 2 16x16 matrices. I have them connected with Dupont wires. I also power the 2 16x16 with Dupont wires that are connected to a 5v 60Amp ...
-1
votes
2answers
40 views

I need help makeing a light flash while a stepper is constantly moving

The starter code. #include <Stepper.h> const int stepsPerRevolution = 120; // change this to fit the number // for your motor of steps per revolution // initialize the stepper library on ...
0
votes
1answer
39 views

Trying to Pulse an LED a number of times outside of the main loop

I'm trying to call a class function that pulses an LED "x" number of times. I dont want to use a delay, which is making it tough. If I use a while loop, the LED just stays on. I attach an interrupt in ...
-3
votes
1answer
25 views

How do I turn on/off led with the same IR button? [closed]

I'm trying to make the led switch on/off by the same case(): code. But its not working could anyone help me?
0
votes
3answers
83 views

Do I need a pull-up/down resistor for button LED circuit?

When reading up on how to make a circuit that turns an LED on when a button is held down, I keep finding people saying a pull up or down resistor must be involved, to avoid the flickering state of the ...
0
votes
0answers
185 views

What's the required voltage for ws2815?

I am working on ws2815 led strip with the esp8266 on arduino 1.6.6 fast led library.Using CD40109B level shifter to convert 3.3V of esp output to 12V .It's working fine upto 31 leds according to the ...
1
vote
1answer
29 views

Assign and control Digital pin from String

Here is modified version of Blink example #define D8 13 String p = "D8"; // the setup function runs once when you press reset or power the board void setup() { // initialize digital pin ...
0
votes
2answers
167 views

74HC595 shift register not working

I got my Arduino kit a few days ago and I've been going through some of the tutorials. I got to the 8 LEDs with a shift register tutorial, where I got stuck. Nothing would light up after I plugged ...
0
votes
1answer
30 views

What are the purposes of the different LED lights on a Arduino UNO board?

The LEDs namely L, TX and RX on the board. Furthermore, whenever the board is connected, the L LED blinks to the frequency of the delay that I set. [Eg: delay(1000);] If I miss any other LED, do ...
0
votes
1answer
41 views

20 m LED WS2811 Pixel Stripe 12 V

i need some help for my masterthesis. I plan an Light and Sound installation and for this I decided to use the shape of an Dodecahedron and I want to put LED RGB Pixel Stripes on the surfaces to light ...
0
votes
2answers
58 views

Methodology for designing/prototyping LED patterns

Several of my projects go through this time-consuming and tedious phase: design a LED pattern for a geometry of WS2812 LEDs implement it with e.g. FastLED write to Arduino and see results goto step 1 ...
0
votes
1answer
77 views

Arduino button-controlled LED with AVR Assembly

I am trying to make a simple button-controlled LED, but I cannot seem to get any input from the button that would change the state of the LED. In other words, the program keeps branching to lighton, ...
1
vote
0answers
137 views

LED strip with 12v power connected to ESP32

I'm looking at controlling a ws2811 strip and I have seen mention that you should share the same ground between the strip and the controller, which does make sense. I do not currently have a proper ...
2
votes
1answer
127 views

LED intensity on digital pins [duplicate]

I am using an Arduino UNO. On any digital/analog pin, if an LED (with resistor) is connected and we use digitalWrite(pin,HIGH) the LED lights up rather dimly. On the other hand, if we use pinMode(...
0
votes
1answer
71 views

Controlling LED and Button with single pin

I am trying to use an ATTINY85/Ardunio Uno to turn an LED on and listen to a button input. I don't mind if the LED turns on when the button is used. I am have found this thread from a couple of ...
1
vote
1answer
39 views

Sanity check for dual IR LED circuit [closed]

If the intent is to drive the two LED's with 200-400mA (using PWM @ 38Hz), is there anything wrong with this solution? Perhaps this is a better solution, as it ensures the current is exactly the same ...
0
votes
1answer
44 views

Reading analog value while generating PWM signal

I'm trying to generate dim two LED strips simultaneously by generating two PWM signals based on potentionmeter value. The pot sets how bright each of the LED strips will be. To drive this I'm using ...
0
votes
2answers
123 views

could not convert 'digitalWrite(8u, 1u)' from 'void' to 'bool'

I am trying to make some LED lights to turn on when i flick a switch on my RC crontroller. I will connect the signal wire from RC controller to pin 8. The plan is: if i flick the swich, the LED's (pin ...
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votes
2answers
74 views

Turn on Indicator LED if Moisture Sensor Value >= MaxDryness for longer than 20 min

Hi so I am making a self watering flower pot with a moisture sensor and a peristaltic pump, the code is as follows: I want to add an indicator LED which turns on if the sensor value has been equal to ...
0
votes
1answer
78 views

How to fix this code so instead of having to hold button to change led, you can press?

const int buttonPin = 1; // the pin number of the pushbutton input pin const int ledPins[] = {2, 3, 4, 5, 10, 11, 12, 13}; // variables will change: int buttonState = 0; // variable for reading the ...
0
votes
1answer
89 views

Problem with interrupts

Alright. This is what I wanted to do: Make a circuit and code the arduino such that there are 2 tactile switches, each with a predefined pwm value. Whenever any one button is pressed the led should ...
1
vote
3answers
67 views

Detecting pulsed LED

I am trying to use an Uno to detect if an LED is on or not. Sounds simple, but I am tearing my hair out on this one, here is why.... This is a model railway application and I want to detect an LED ...
0
votes
1answer
41 views

Help with simple gradually brighter flickering led

im a newcomer for arduino and sorry for any grammar error. So what im trying to do is replicating a flickering effect found on spacecraft thruster when they about to take off where the fire bursting ...
0
votes
1answer
52 views

Serial monitor doesn't work with piezo buzzer

So I can't see the distance of the proximity sensor anymore as soon as I type the code for the piezo buzzer. I've tried many things but it doesn't work.. Can anybody help me fixing this? int trigPin =...
-1
votes
1answer
242 views

ESP32 Dimmable LED Panel with MOSFET [closed]

I want to use ESP32 to control and use a dimmer for 6 LED panels in my bedroom. The specification of each panel is mentioned in the diagram. Although in the diagram it shows ONLY 1 MOSFET and 1 LED ...
-1
votes
1answer
36 views

How do I know if my Arduino is connected to my LEDs?

I have an Arduino Uno and a string of WS2811 LEDs. I am still trying to get started on this project, which is creating a Stranger Things wall. I've installed FastLED and uploaded the sample program "...
1
vote
2answers
492 views

Connecting 12V WS2811 RGB LEDs to Arduino Uno & 5V Power Source (Breadboard needed?)

I have an Arduino Uno, 12V WS2811 RGB LEDs (from Mokungit), a 5V power source, and DC power connector. I do not have a breadboard and hope I don't need one. This is almost exactly what I need to ...
0
votes
1answer
55 views

How to regulate a led on-board? [closed]

There is blink project consisting 3 sections: 1 - regulation of the led brightness using a potentiometer 2 - whenever: the button is pressed - the led is on - the button is released - the led is ...
1
vote
1answer
103 views

5 switches, 5 leds, 5 tones, in an Array

The idea is when a switch is pushed, the corresponding tone will be played as well as lighting up the corresponding LED. I have the circuit set up to where each array matches another, for example ...
1
vote
1answer
360 views

FastLED fill_rainbow - Unexpected red pixel

I'm using FastLEDs builtin fill_rainbow function for generating a rainbow spectrum on an LED strip. The issue is, I get a random red pixel midway through the yellow region. I've tried it on 3 ...
-1
votes
1answer
191 views

Dimming multiple leds with pot meter [closed]

I'm working on a small project. I have 13 leds which need to be controlled individually (turn on or turn off); Since I don't have 13 pwm pins I used a potentiometer to change the brightness. This ...
1
vote
0answers
28 views

TLC5917 SPI Speeds

I am attempting to use 3 x TLC5917 chips to drive a row of LEDs in PWM. The LEDs share a common anode being powered through a transistor, with each LEDs cathode going to pins on the TLC5917 Chips. ...
0
votes
4answers
74 views

help with a loop

I recently got into programing and I'm making an alarm. I cant figure out how to make a buzzer loop. I have two blinking LED's and two fading ones. Now I plan to have sound and it won't work. It only ...
1
vote
2answers
120 views

How can you have two blinking leds and a fading one

I am trying to make a alarm and I have two blinking leds (red and blue). They work fine but I want two more that fade in and out. I have a buzzer on it too. I am very new to programming. By the way, ...
2
votes
2answers
58 views

Using two sensors with delay concurrently

I want to use an ultra-sonic sensor and the led concurrently. I want the led to blink every 0.2 seconds and the ultra-sonic to measure distance without regard to the blinking. The problem is I have ...
1
vote
1answer
183 views

Midi controlled LED by USB [closed]

I am trying to create something that will allow me to control an individually adressable LED strip using an electric piano using its midi output. Some things to note: The piano can output midi ...
-1
votes
1answer
35 views

Adjustable temperature [closed]

How can I make a project where I can adjust a temperature with buttons and a display and if the temperature is higher than that I set, a led turn on ?
1
vote
1answer
90 views

Arduino UNO LED half brightness when connected to digital GND but not analog [closed]

I am using an Arduino UNO. When lighting an LED with the switch button on a joystick module, I have two situations: If the LED's cathode is connected to GND on the digital pin side of the Uno, the ...
-1
votes
1answer
91 views

how to connect 100 Leds and Blink them on Arduino [closed]

I am planning to connect 100 LEDs to an arduino in a parallel circuit. The current limit exceed beyond the Arduino UNO board. In want to blink all 100 LEDs at same time. So how can I provide power ...