Questions tagged [led]

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

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186 views

Working with multiplexers for constant voltage output

I'm working on creating a circuit where I'm trying to have the ability to switch multiple strands of LED rope on and off at a time using an Arduino and a multiplexer. With my current configuration, ...
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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 ...
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569 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 ...
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1answer
126 views

Blynk app, DotStar bluetooth control code help

This is my setup: Arduino Mega; HM-10 bluetooth module (bought off ebay, so not sure if genuine but works); Adafruit Dotstar addressable LED strip; iOS Blynk app; Hardware-wise, everything is ...
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1answer
45 views

Troubleshooting WS2812B LED strip

I am doing a project for my master thesis and I have 6 stripes of WS2812B LEDs each one containing 77 LEDs. I finished the design and now want to turn them on. I used an old power supply to power it, ...
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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 ...
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1answer
56 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 ...
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1answer
40 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 ...
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1answer
75 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 ...
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1answer
265 views

Breaking out of a while loop using IR remote for neopixel

I've been piecing together various lighting effects. I am wanting to have each lighting effect loop until another button is pressed to trigger another lighting effect. I've come to a bit of ...
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1k views

Arduino sketch works on ATmega1280, but doesn't work on ATmega328 (Arduino Nano)

I'm working on arduino based RGB LED strip controller. This simple schematic was used to control 12V channels via 5V PWM signal from arduino: I have also connected an HC-05 bluetooth module to be ...
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39 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 ...
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259 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 ...
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36 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. ...
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68 views

Do I need one N3904 for each LED?

I want to control 4 (or more) LEDs using the PWM output pins of my Arduino. Here is how I have it on a breadboard, and it's working for me. Question: Is this schematic inefficient? Are there any ...
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39 views

Arduino Uno LED not working

so I'm new to all this Arduino stuff and have been trying to get into it, starting off with a simple project/test but have been having some issues. I followed the set up the book provides, and am ...
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612 views

Switch on/off LED 24V using a MOSFET

I try to switch on/off IKEA Ledberg LEDs which are powered with 24 V using the setup from this tutorial video: https://www.youtube.com/watch?v=sVyi7yWuXxs I use a IRLB8721PBF MOSFET. When I switch ...
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155 views

Sparkfun Spectrum Analyzer: Problems with frequency bands

I bought around 2 years ago the Spectrum Analyzer Shield from Sparkfun, but I never had the time to do something with it. Recently I found the time to start a project to build a graphical equalizer. ...
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185 views

LED Webserver control not working

I've got an Arduino Uno and Ethernet shield, trying to test it out with a simple on off switch for the on-board LED. My Code is this // FILENAME = LED2.ino // SOURCE= http://www.instructables.com/id/...
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807 views

troubleshooting - Turn on a single led in a ws2811 ledstrip with an arduino Uno with FastLed

I want to to turn on a single led in a ledstrip running on ws2811 with an Arduino Uno. The problem is that when I try to turn just one of them on, they all three light up. The strip is a 3-wire ...
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518 views

Testing for bad WS2812B?

I bought a 100 pack of WS2812S SMDs last year (product link) and wired most of them together for a string of Christmas lights for a tree. It was more work, but way cheaper (at the time) than buying a ...
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0answers
74 views

Determining if an LED on another device is on

I'd like to check if this circuit I'm making is correct -- I'm concerned I'll mess up my Arduino. Essentially, I would like to determine if an LED on another device is on or not by measuring the ...
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251 views

Help with Arduino Due and APA102 LED strip Vs Matrix

I am in a fix since last one week regarding this: As mentioned in a previous question (asked here only), I have been working to develop a APA102 LED based display. Now for this I have an Arduino Due. ...
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264 views

Parallel Chaining of APA102 LED matrices

I have four APA102 LED matrices (those flexible ones) and I want to connect them together to make a display for showing images. Now my problem is this: Consider the coordinate system with four ...
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0answers
213 views

Parsing UDP text from a Command using UDP

I want to send a parameter from my computer (i.e using Hercules software) using UDP protocol to my Arduino with Ethernet shield to turn 2 LED on and off (each of them). The command I'm using is: $A&...
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334 views

Bluetooth shield with ardudroid RGB LED

Here is their code: /* PROJECT: ArduDroid PROGRAMMER: Hazim Bitar (techbitar at gmail dot com) DATE: Oct 31, 2013 FILE: ardudroid.ino LICENSE: Public domain */ #define START_CMD_CHAR '*' #...
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0answers
1k views

Blinking LEDs as fast as possible at different rates.

I'm trying to use the Arduino Uno to make a strip of LEDs blink as fast as they can while still blinking at different rates. I am able to get them blinking at different rates but the blinking is very ...
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0answers
760 views

Arduino PWM LED blinking on four pins, each pin's intensity and time period based on the previous pin

I am trying to make four LEDs glow using my Arduino, based on some relationship between them in terms of brightness and the time for which LEDs glow. For example, the relationships are: pin_3_value =...
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217 views

Arduino based temperature sensing circuit

I've currently got a setup where I am using a 2 thermocouple setup using MAX31850 and the circuit looks exactly as mentioned here using the external power option. (https://learn.adafruit.com/adafruit-...
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446 views

Pro Mini 3.3v + Neopixel not working when disconnected from USB

I'm doing a project using an Arduino pro mini 3.3v and Adafruit's Neopixel. I've flashed an example (strand example) from the Adafruit Neopixel's library sketch into the Arduino using the FTDI Basic ...
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447 views

What bytes do I send to the MAX7221 to light an LED (in an led Matrix)?

Datasheets LED Matrix (p2): https://www.circuitspecialists.com/products/pdf/M105057CHR1.pdf MAX7221: https://www.sparkfun.com/datasheets/Components/General/COM-09622-MAX7219-MAX7221.pdf ...
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280 views

Connecting Indicator LEDs to Arduino Pro Mini

I'm new to electronics and unsure whether my design below will work as intended. XBee Series 2 and Arduino Pro Mini 5V are used. There are 4 LEDs, each with the following roles: LED1: Flicker when ...
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0answers
550 views

7 Key Educational Piano with Capacitive Sensor

I am working on a project for grade 10 computer science. I am supposed to make a piano that has 7 keys using a capacitive sensor, and the piano is supposed to teach you songs like Twinkle Twinkle ...
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0answers
2k views

Controlling multiple LED strips with arduino

I want to control several (undecided) cut strips of these led lights:here. I want to be able to turn the LEDs on and off from the arduino, but I know that the voltage is too high to work with with ...
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0answers
1k views

Controlling LED delays via keypad

I'm trying to turn on LEDs based on delays entered by keypad and the same for turning them off, but the LEDs are not responding. Here is the code I'm using: #include <Keypad.h> const byte ROWS ...
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9 views

Communication using two HC05 modules

I'm working on a project that consists of sending data from flex sensors from a master Arduino to a slave arduino that uses that data to control servo-motors. I am trying to start slow and just ...
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0answers
32 views

LED doesn't turn on as specified on code State Machine

This is the question from the homework I'm doing "Design and implement a state machine with a single button to turn on and off two LEDs The first LED should be turned on and off with a quick press of ...
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30 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 ...
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0answers
55 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 ...
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0answers
30 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 ...
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0answers
81 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 ...
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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 ...
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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 ...
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0answers
575 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 ...
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109 views

Lighting up long led strip no longer works when my code grows

I have a 144 LED strip - Adafruit NeoPixel Digital RGB LED Strip 144 LED, link here: https://www.adafruit.com/product/1507 If I create a simple project, eg turning pixels on off from the serial ...
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145 views

256 (8x32) LED Matrix via ESP32-Pico-Kit_V4 possible? (Daft Punk Helmet)

I am currently planning on a Daft Punk Helmet. But the available kits are terribly expensive. I am looking forward to using a 8x32 LED-Matrix(with 256 separate 5mm LEDs) and having a few different ...
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33 views

How to upload data to program over USB port

I am working on a set of Visual poi (like these https://lighttoys.cz/store/vpoi/v4/) and need to upload new pictures to the controllers every now and again. Currently I use a program to convert a ...
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222 views

Can 2 or more LED strobe Lights Flash in Sync?

I'm trying to build a strobe light that has at least 1 mode that can sync with another unit. The strobe light has 2 colors, white and red which are driven by 2 qlite drivers which are controlled by ...
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84 views

Arduino Code hang

I am working on a project to dim/brighten the LED lights between each hour. To make the program readable i have only kept the code for few hours. For example if T1 is at 255 PWM and T2 is 20 PWM, the ...
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105 views

Safe way to setup I/O to read switch AND manipulate LEDs at the same time

I would like make educational shield for playing with Arduino, where (at least couple of) pins would be connected to grounded switches (so could be configured as INPUT, or INPUT_PULLUP a digitalRead() ...