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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
820 views

Control LED strip IR controller using Arduino

Is it possible to connect to one of these, which run at 12v, to turn on the LED strip using an ESP8266? It doesn't matter if it's an Arduino or the ESP8266, both should be able to do this. The board ...
0
votes
0answers
120 views

Arduino: Output state of pin (~3) running PWM signal. Is it ON or OFF?

On my Arduino UNO, I have set pin ~3 to run PWM. Is there a way to know when the signal is ON and when it is OFF? I am trying to eliminate background noise from an LED light intensity reading by ...
0
votes
1answer
77 views

Arduino UNO Intro to Engineering Project [closed]

I am a college student in an intro to engineering class looking to create a final project. My goal is to create a small "present" that opens its lid via a servo and plays jingle bells with LEDs ...
0
votes
4answers
3k views

Using a button to toggle an LED ON/OFF

I'm fairly new to Arduino and am trying to use a push button to toggle an LED on and off using a momentary press of the button. This code is lifted straight off the tutorial on the Arduino website but ...
1
vote
2answers
90 views

Turning a motor on and a led at the same time for a given time period

I need help with this code, I want to have a motor turn on for a given time and at the same time have an led light up to indicate it is on which will also turn of once the motor has stopped. It is ...
1
vote
3answers
474 views

Analog input draws current when Arduino is turned off

I am using a Arduino Pro Micro from SparkFun (similar to Arduino Leonardo, cpu: Atmega 32u4). It has a analog input: A0, which I use to keep track of the battery voltage in my battery powered project (...
1
vote
1answer
92 views

8 x 8 led matrix module [closed]

I just bought 4 8x8 led matrix module from online store...when I connect the led module to arduino and computer without any program, the led shows weird pattern (isn't that is should show all 64 led ...
1
vote
0answers
544 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 ...
0
votes
1answer
149 views

Arduino Mega 2560 LED is dim when powered from digital output

My circuit is a simple one, I am using an arduino atmega 2560. One 5mm red LED connected in series with a 150 ohm resistor. If I didn't make some kind of goof, a red LED has a voltage drop of 2 volts ...
1
vote
3answers
359 views

How do I call functions sequentially without using the Delay function?

I've been messing with the Adafruit Neopixel lib, and I'm trying to replace some of the delay functions with mills ( so that I don't block the serial port ). So far I have the following code; void ...
1
vote
2answers
358 views

How do I set a continuous servo to turn on until a switch is flicked?

I am trying to get a servo to be activated by a momentary button. The arm on the servo will then swing around, which then activates a toggle switch. The activation of this toggle switch will then ...
1
vote
0answers
140 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. ...
0
votes
1answer
583 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
votes
1answer
106 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
vote
3answers
460 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
votes
1answer
50 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
754 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
votes
1answer
611 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 ...
0
votes
2answers
79 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
votes
2answers
909 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....
1
vote
3answers
856 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
votes
2answers
54 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, ...
0
votes
2answers
554 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
vote
3answers
592 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
votes
2answers
722 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
vote
2answers
154 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
votes
2answers
84 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
vote
1answer
870 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
181 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 ...
0
votes
2answers
89 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
vote
1answer
55 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
287 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
421 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
470 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 ...
1
vote
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
145 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 ...
0
votes
3answers
48 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
658 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
vote
2answers
374 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
764 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
268 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
115 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
vote
3answers
81 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
vote
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....
0
votes
1answer
307 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?
-5
votes
3answers
109 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
vote
0answers
172 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/...
1
vote
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
167 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 ...