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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.

3
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0answers
42 views

Red LED not turning off on Adafruit Circuit Playground Classic

When using the traditional Blink example program, the light blinks as expected. Even when writing from scratch digitalWriteing pin 13 to high and low repeatedly works fine. The problem is when I try ...
-1
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2answers
29 views

Arduino Mega control panel (LEDs and buttons) - custom shield? [on hold]

My main question is - what is the best way to control ~10 LEDs and ~15 push-buttons with an Arduino Mega, given that each LED needs a couple components, and I'd rather avoid using breadboard wires as ...
-1
votes
1answer
42 views

Measure duration of LED pulse and conditional serial print

Casual Arduino user with some programming experience here. I am trying to build a system to integrate with another board which switches relays based on serial data received. I have a status LED that ...
1
vote
1answer
18 views

Press one button then another?

Let's say we have two buttons - button 1 and button 2. What I need to do is to do something (like turn LED on) when button 1 is press, then button 2 is pressed. I can do it realy simple by just using ...
0
votes
1answer
20 views

I am not able to set the correct configuration of sound module

I have been trying to make sound reactive LED lights but my sound module is detecting only very close voice the LED react only when I press it to the speaker with my hands I have tried to set the ...
0
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0answers
27 views

On the LEDs WS2812C

I've got a few questions about these LEDs (WS2812C). According to what I understand in the data sheet, they are adressable RGB LEDs with 4 pins: VCC, GND, DIN,DOUT. I'm working on a project that is an ...
0
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0answers
33 views

Programming POV Display for Arduino

I can maybe work through a php/sql and css/html method of making a website to convert an image to code, but that is currently a time consuming method (which i will be taking the challenge if doing ...
1
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1answer
32 views

Serial input help

Hey guys I have a LED strip with 6 LEDS (I control these through Kinect & processing. It sends 1,2,3,4,5,6 to Arduino. This seems to work fine.) In Arduino LED0,LED1,LED2,LED3,LED4 work ...
0
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2answers
34 views

Receive Signal from different circuit

I am an mid experienced Programmer but I have no clue about electronic circuits. I want my Arduino to do sth if he gets a signal from an external source. The external source has 5V and is 0V or 5V and ...
0
votes
1answer
22 views

Output pin low used to complete 12V LED circuit?

I have a project that (in part) will drive 3 LEDs where the LED anodes are at 12V. The thought is to drive each LED by connecting each cathode to a 650 ohm resistor, and connect that to an Arduino ...
0
votes
2answers
36 views

How many Amps can a Nano Arduino hold for LED project

I'm really new at this, and here is my doubt. What if I need to light 120x WS2812B (5v)LEDs (link: LEDs) using an Arduino Nano? if it takes 60 mAh each pixel, the total amount needed should be around ...
0
votes
1answer
18 views

Using an Android bluetooth terminal to change preset states on 8x8 LED matrixes

I'm trying to create eyes for a project, and while I have been able to properly program the different expressions, and have them triggered by commands from the COM3 terminal, I have not been able to ...
1
vote
1answer
36 views

Using 18650 batteries with a 3.7v to 5v boost converter [closed]

I'm looking to set up a 1-meter strip of WS2812B LEDs (60 LEDs) with an off-the-shelf RF LED controller with a remote. The LEDs want a 5V supply - I've tried running them off 3.7v but the colour ...
0
votes
1answer
43 views

Is SPI a good way to connect two rfid modules on separate arduino boards?

RFID access control I have two separate rfid projects on separate arduino, the first project requires 2 minutes of contact between the tag and the reader after which it turns the LED on. the second ...
0
votes
1answer
37 views

Why can't I switch off the LED immediately using this sketch?

I hope the LED can fade out a period of time. Also, I hope I can switch off the LED immediately when it is fading, but I only can fade out. const int buttonPin = 2; const int ledPin = 9; const int ...
0
votes
1answer
63 views

Is there a way to have the LED switch on after 10 readings or say a minute?

I am using Arduino for a RFID project where the LED must switch on after either 12 readings of the tag or 2 minute, the tag reading happen every 10 seconds. I can't seem to figure out a way to have ...
0
votes
1answer
37 views

PWM Control, How to stop LED from Flickering?

What is required is controlling the brightness of an LED using both Buttons and a Potentiometer, Button A: Increase Button B: Decrease /Dim Potentiometer: Increase and Decrease, This however must ...
0
votes
1answer
44 views

AtTiny analog read always 1023

I am trying to replicate Low power LED firefly project. So what I'm trying to do is to do an analog read from a LED, to detect light. To simplify it a bit, I am using different pins and different leds ...
1
vote
4answers
675 views

changing state of an LED using a pushbutton leads to unstable result

I am trying to run this code: const int buttonPin = 7; const int ledPin13 = 13; int buttonState = 0; int lastButtonState = buttonState; bool flag = true; void setup() { // ...
-1
votes
2answers
34 views

How to hook up led matrix 1088AS to a PCA 9685 servo controller? there is a way?

I'm confused about the pinout, I can't figure out which physical pin of 1088as red led matrix must to hook up to the PCA9685, if there is a way to do this I found this image the final target is to ...
0
votes
2answers
88 views

LED on same Pin as Toggle Switch, not illuminating

I am trying to do something I think should be relatively simple. I would like to read an input from a toggle switch, and have a red 5mm LED indicate the state of the switch. Rather, however, than have ...
0
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0answers
26 views

Using a 48 characters char[] for PROGMEM

I am trying to create a charliplexed display of 6x8 LEDS using a Arduino Nano with the ATMega328p chip. Because of the limited storage I am trying to use PROGMEM. I did my research and found some ...
0
votes
1answer
46 views

MAX7219 and Arduino

I am getting started in running this 8x8 led on an Arduino. Regardless of which tutorial sketch I attempted, I never got a scrolling text that I expect. What happens seems to be only a single (out of ...
0
votes
1answer
39 views

connection of led with dht and code combination

Hi again? I saw my last question did not come out well, so let me rephrase it. Ideally, my project is composed of 3 sensors: 2 dht-22 sensors and an mq-7 sensor. For the dht22 sensors, I am using ...
0
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2answers
55 views

7 LED Number Display

I need to write a string of number such as 1234567 on a 7 LED display. For example 1 will be lit up on display for 0.5 seconds, it will turn off then 2 will light up and so on. In the end I need to ...
0
votes
0answers
59 views

Multiple Servo motors with an ultrasonic sensor

I am building a robot arm with 6 servo motors that works with an ultrasonic sensor. The purpose of the program is when an object is detected at 20 cm (fixed position) from the sensor, the buzzer and ...
0
votes
2answers
51 views

Reading Digital Pins and Outputing on entire Ports

I'm very new to coding so please don't grill me. I'm working on a scientific project where I am using a NI-DAQ to digitally trigger mosfets to trigger 300us - 3ms pulses on two high powered LED ...
0
votes
1answer
37 views

1st LED turn ON when 1st button is pressed and other LEDs remaining OFF

I have 2 LEDs and 2 buttons. What I want to code is when first button pressed the 1st LED turn on (stay on for 5 seconds) and 2nd LED remain off, and same if 2nd button pressed the 2nd LED turn on and ...
0
votes
0answers
33 views

Cannot give battery through USB cable

I just make a simple circuit with uno and breadboard ,that connected 4 LED and 4 IR sensor. The arduino program is simple that makes the light on or off with the determination of IR sensors . However ...
0
votes
1answer
40 views

Problem with SPI when using rf24 NRF24L01 transceiver with LED matrix MD_MAX72xx

I am currently using Arduino Mega to use a LED matrix and a NRF24L01 transceiver. for LED matrix, I use MD_MAX72xx library. While for the transceiver I use the RF24 library. I am already able to ...
-2
votes
1answer
43 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
33 views

Component with controllable resistance from Arduino? [closed]

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
69 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
37 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
38 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
53 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
28 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
22 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
114 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
77 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
40 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
24 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
41 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
41 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
26 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
157 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
458 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
35 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
278 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
58 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 ...