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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.

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1answer
530 views

Using Multiple 4 Digit displays with the same pins

I currently have a ton of 4 Digit 7 Segmented displays(TOFD-5465GGH-B). The display is driven by a PT6961 LED Driver. Using a Library that I found here I was able to use the display with no issues. ...
0
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1answer
97 views

Minimum number of Pins to use for multiplexing LEDs

whats the minimum number of pins to use when multiplexing 6 LEDs? is there some kind of formula that can be applied to n LEDs? Or in other words, how many LEDs can an Arduino Uno control without the ...
1
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3answers
361 views

LEDs not working with tone() function

I have a strange issue. I have 3 LEDs, each is supposed to beep with a correlated tone... Imagine the beginning of a racing game (beeping with traffic lights). Here's my code: #include "pitches.h" //...
0
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1answer
48 views

Traffic lights: gpios against 5V or ground

I have 3 standard LEDs (red, yellow and green) connected in parallel to GPIO pins 10, 11 and 12. I also have one resistor, to which they are all three connected. What's the difference between ...
4
votes
1answer
562 views

How many Infrared sensor modules can be added to a single Arduino (eg;Uno)

I am looking to add block detection to my model railroad. I need approx. 40 infrared sensors to power 40 LED's on my control panel. No signals or other logic required yet, just the LED indications -...
0
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1answer
513 views

MAX7219 7-segment 8-digit display in wrong order

I have daisy-chained three MAX7219 7-segment 8-digit displays and wired it according to this diagram: but no matter what library I use, the middle segment is in the wrong order when I display it. So ...
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2answers
71 views

Current Draw for LED Projects

I am working on a project with LED strips that would consume 12V and 20A. The problem is that the household wall outlet limitation is 15A, and 20A current draw would potentially start a fire. I have ...
2
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2answers
622 views

Changing the order of blinking LEDs with the push of a button

I am new to Arduino and I have written code that makes 3 LEDs blink while the push button is off, so the lights are blinking from left to right (1,0,0)(0,1,0)(0,0,1) and then repeat from left to right....
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3answers
748 views

ESP8266 blink sketch not blinking LED

After flashing the blink sketch to the ESP8266, I removed all the unnecessary wires from flashing - and my setup to try and run the sketch looks like this: Something to note about flashing - it would ...
0
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2answers
49 views

LED matrix question light up H or 4

Just a basic query; On my understanding of LED Matrix's, The following would light up 4 LEDs. But what if I only wanted to light up just 3 of those LEDs? The circuit still needs the same inputs, ...
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2answers
484 views

ESP8266 Blink sketch - does not blink / or stays constant

I uploaded the Blink sketch (from the ESP8266 examples, in the Arduino IDE) successfully. Depending on which wire configuration I am using two different things happen: wiring 1: CH_PD -> 3.3V ...
1
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3answers
492 views

Blink a LED between servo pulses

Apparently using delay() commands locks the Arduino during the delay period and there are better ways to control a servo that free the Arduino to do other things at the same time as running the servo. ...
0
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2answers
583 views

Arduino Uno simple LED example with pointers

I am new to Arduino and I have recently started off by trying to turn on an LED connected to pin 13 on my Arduino Uno using pointers. I opted to do this with pointers because this would give me a ...
1
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2answers
139 views

Get a LED to fade out

I want to light an LED in a sketch and then have it fade out. I tried to use analogWrite and have it decrease from a value of 255 to 0 using a for() loop, but I can't seem to get it to work. Using ...
3
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2answers
83 views

just a silly doubt about glowing an LED

what will happen if i insert the anode of a LED to pin 12 and cathode of the LED to pin 11 and set pin 12 to high and pin 11 to low,will the led glow??
1
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1answer
758 views

WS2812 (?) RGB LED matrix turns on white

I have an RGB LED 8x8 matrix which is claimed to consist of WS2812. When turning it on, it automatically lights up all LEDs white with full brightness. The LEDs even light up without DIN being ...
2
votes
2answers
179 views

A beginner lost at sea, Arduino looking at the sun [closed]

I am working on trying to make a LED strip respond to natural Light levels for a sculpture. I have reached a problem in trying to get the code to work when sending PWM to the light strip. Thank you ...
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2answers
82 views

Fade sketch stuck in mathematical loop

I tried to edit the Fade sketch such that the max intensity the PWM reaches is controlled by a potentiometer. I used analogRead() on the potentiometer and converted the 10bit value to 8bit equivalent(...
1
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1answer
53 views

Advice on cabling, packaging and connectors for 12v light project [closed]

My project is to have a 12V solar LED strip lighting system throughout my apartment. This has 6 individual lights, with 5 white and 1 RGB = 8 channels. I've got the whole setup working on my ...
2
votes
1answer
1k views

Breaking out of while loop using IR remote input

I'm trying to control a series of LEDs using an IR remote. I have a problem when I try to play a sequence with the LEDs where they all light up in a line and turn off accordingly. I loop through the ...
2
votes
2answers
228 views

Particle Spark (Arduino) How to flash 2 LED sequences at the same time?

I can't find any information that relates to my problem. The few things I did find confused me (I'm quite new to this). I'm trying to flash 2 sequences of 4 lights at the same time. I can get 1 set ...
0
votes
1answer
351 views

Low power RGB LED for wearable device

I am trying to prototype a wearable device which will have about 120 RGB LEDs. I was considering the WS2812B but they seem to draw about 50mA and so may not be a good option since I will be powering ...
0
votes
1answer
406 views

Arduino Wire communication with MCP23008 GPIO pin expander to turn on an LED with a button press

I am using an Arduino Uno and an MCP23008 GPIO pin expander, I have a momentary button connected to GPIO 2 on the MCP23008 and an LED light connected to GPIO 1 on the MCP23008. What I want is for the ...
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3answers
2k views

How to detect if LED is switched on in external circuit using Arduino NANO?

I want to detect when an LED is powered on using an Arduino NANO. The LED is part of an external circuit. The LED uses about 1.8V. Would the circuit below allow me to detect when the LED is switched ...
2
votes
3answers
120 views

Controlling 10+x 5m led strips with 10+ individual analog floor switches

I am looking to control around 10 (exact number TBD) non-addressable 5m led strips with an Arduino. Each led strip will be activated when a corresponding DIY analog floor switch. The idea is to have ...
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3answers
47 views

Why did my pushbutton LED circuit work when my wiring was wrong?

I had a Coursera Arduino homewhere wherein you create a simple pushbutton-controlled LED circuit. I used the example "button.ino" script that's builtin to the Arduino IDE, without modification. I'll ...
3
votes
1answer
558 views

MAX7219 with Arduino UNO - LED control doesn't work

I'm very new to Arduino and this is my first project, so I may misunderstand something simple. As a hardware I'm using 4 MAX7219 connected to Arduino UNO and a single diod for tests. As a software I ...
1
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2answers
313 views

PushButton as LED Switch (does not work)

#define LED 1//This pin goes to the LED #define SWITCH 7//From Switch$ void setup() { pinMode(LED,OUTPUT); pinMode(SWITCH,INPUT); } int state=0;//Initializing values of all ...
5
votes
1answer
639 views

EPS8266 ESP-01: LED manipulation seems to interfere with serial communication

I'm playing around with this udp-example. Both this and the blink-example work perfectly. Now I would like to use the LED to indicate what the ESP is currently doing, as well as reading some data over ...
3
votes
2answers
226 views

How can I connect nearly 450 LEDs to an arduino without drawing too much current?

The question seems simple, but there's more to it: I'm connecting 4 74HC595 shift-registers to an arduino pro micro. 28 of the 32 outputs will be used to control LED segments of numbers. Each segment ...
1
vote
1answer
99 views

Charlieplexing 30 LED sections with a max of 27 LEDs at the same time?

So basically, I'm trying to make a digital wall clock and using digital numbers, I have 7 sections of LED's per number, 4 numbers and one section for the colon in between them. A total of 30 sections. ...
1
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3answers
75 views

LEDs Randomly smooth transitioning, accounting for black or how-to switch using HSV

I am stuck trying to get it not to account for black in RGB. My first instinct was to use the HSV color spectrum over the RGB rainbow but, the same code will behaves differently in HSV. If i could ...
1
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3answers
1k views

Function for converting milliseconds to minutes?

I'm playing around with a Neopixel strip and want to be able to enter the amount of minutes I want an LED to do something rather than in milli seconds. So for example, void loop() { colorWipe(strip....
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1answer
274 views

LEDs on Arduino WiFi Shield

I would like to know the purpose of the LEDs on top of the Arduino WiFi Shield: L9/Link/Error/Data (left in the picture). What do they indicate?
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3answers
99 views

ARDUINO led bar indicator if/for/else [closed]

Thanks to anyone willing to help! this is my first weekend arduino tinkering. i have an ARDUINO pro mini i attached 6 leds on pin 2-7 i attached two push-buttons on pin 10-11. I want the leds to light ...
1
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0answers
162 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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2answers
69 views

How to add this old BASIC code snippet to work in Arduino C++ for FastLED?

I've been trying to implement this old code that randomly transitions to RGB color into my Arduino board that uses FastLED. Static Col1, Col2, Col3 As Integer Static C1, C2, C3 As Integer If (Col1 = ...
0
votes
1answer
138 views

Coding or Wiring? Dual Piezo sensor not triggering LED lights

I am running two piezos off an Arduino UNO and trying to get 10 LED lights to trigger when the piezo voltage exceeds a certain threshold. Problem is, the LEDs wont fire when the Piezo voltage exceeds ...
1
vote
1answer
269 views

How do I connect a LED strip to a Multiwii SE 2.5?

https://www.m.nu/neopixel/mini-skinny-neopixel-digital-rgb-led-strip-60-led-m-black-pcb-1m I just purchased this led-strip that I plan to use with my Multiwii SE 2.5. I power the Multiwii itself ...
1
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2answers
489 views

NodeMCU NeoPixel

I am attempting to control a single NeoPixel with a NodeMCU, but I'm not having any luck. Even just loading the default Adafruit NeoPixel library sketch yields unsuccessful results. I've tested the ...
1
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2answers
123 views

Help What am I doing wrong? Matrix Led

I'm new and im trying out the Matrix LED heres my code #include <LedControl.h> LedControl lc = LedControl(12, 11, 10, 1); unsigned long delayime = 100; void setup() { lc.shutdown(0, false);...
3
votes
4answers
172 views

Is it possible to run two for loops separated?

I have three funtion which describe the brightness of three LEDs. I want the seconde loop run 1 second after the first one and the third 1 second after the second one. One loop needs approximately 5 ...
0
votes
1answer
334 views

Buzzing on computer speakers when LEDs are on

I have an Arduino Nano connected via USB to a Mac Mini. When the LEDs come on, an external speaker connected to the Mini starts to hum/buzz quite loudly. If the LEDs are turned off, the buzz stops. ...
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2answers
189 views

15x15x15 LED cube with thermal sensors

I'm trying to wrap my head around a public art project that I've recently received funding for, and I'm hoping that someone here can help me with a bit of guidance. The concept I'm working on is a ...
0
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2answers
66 views

time delayed LEDs

I have two LEDs an I want the first one getting linear brighter and the second one do the exact same thing just one ore two seconds later. When one LED has reached 100, it should getting darker until ...
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2answers
202 views

polynomial change of LED brightness arduino

I try to change the brightness of an LED following the formular in out1. I'm pretty sure that something is going wrong because it doesn't really change its brightness and it never stops lightening. ...
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1answer
98 views

Feasibility of project with 50 leds working independently

I don't have much knowledge in Arduino and I'm about to start a new project which I believe can be done with it. There will be 50 boxes with a led in top of each one. The user will type a number in ...
2
votes
1answer
187 views

Can I power my shift register with a 12V external power supply and connect only the data, strobe and clear pins to the Arduino digital pins?

I'm using a CD4094 shift register to power my LEDs along with a ULN2003A darlington transistor array. I want to hook up the LEDs to an external power supply of 12V (common anode). The cathodes of ...
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2answers
5k views

Arduino code to control 4 led's from 4 buttons

This is my very first arduino sketch and it's causing me a bit of a headache. Sounds so simple really all I want the sketch to do is digitalread from one of 4 digital input pins and then digitalwrite ...
0
votes
3answers
137 views

Two Arduinos get out of sync after a few seconds

I built a small PCB that has some LEDs (bare NeoPixel 5050) and an IR receiver on it. The microcontroller is an ATtiny85, and the PCB is powered by a LiPoly battery (3.7V). The circuit normally stays ...