Questions tagged [arduino-uno]

The Arduino Uno is the most common of the Arduino boards. It is based on the ATmega328P microcontroller.

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Wind speed measuring using Hall sensor

Hi! I require your help regarding a problem I’m encountering. I am trying to measure wind speed using Hall sensor, Neodymium magnet & below mentioned code. But I only get “0” value for both RPM &...
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1answer
47 views

How do I run 4 LEDs sequentially based off of a push button input?

I am trying to create a program that runs 4 LEDs sequentially while also being able to do other things with different inputs and outputs. Because of this, I am using the millis function and not the ...
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How to implement SLAM with Arduino and stores the path memory that it has traversed by an autonomous wheeled robot [closed]

I am very much new in this field ..please bear with me . .I am required to design autonomous robot that moves in random direction in a given area and avoids getting being hit by obstacles placed at ...
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25 views

Serial Connection from ESP32-Cam to Arduino [closed]

I am trying to connect my Esp32-Cam to my Arduino nano. Due to an insufficient GPIO pin on the Esp32, I used an Arduino nano. But I want to have a camera connected to my Arduino nano, and I found that ...
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1answer
24 views

7-Segment Display w/ Potentiometer

(Backstory) So, I took an computer engineering class in high school (grade 11 level), where I learned a bit about breadboarding as well as arduinos (I would like to stress a bit). It has been 5 years, ...
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37 views

Wiring multiple Led Displays to Arduino

I have multiple LED Displays and one Arduino and I just want to show some text on each display separately.(fps doesn't matter because there is a static text or numbers on the screen). Is it possible ...
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26 views

MAX30102 Pulse Oximeter not working

I have recently started using Arduino Uno and wanted to make something that can measure heart rate, SpO2 etc. I have bought a MAX30102 sensor but when I connect it to the Arduino Uno, it doesn't work. ...
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1answer
81 views

Will the pro trinket gamepad library work on an Arduino Uno?

I have an Arduino Uno and I wanted to know if the pro trinket gamepad library works on an Arduino Uno since both have same atmega328p CPU chip.
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1answer
37 views

Servo keeps rotating

I used a 360° servo with a program I made on an Arduino Uno. The program was meant to control two separate servos with two potentiometers on a breadboard. When I used 180° and 90° servos, it worked ...
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1answer
40 views

using RTC for storage

I keep seeing stuff about this: https://www.arduino.cc/reference/en/libraries/rtcvars/ when looking for storage for a few variables that survive turning off and on, but then it is only on ESP8266. The ...
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Shortening array of numbers due to data section exceed warning

I have a sketch with 400+ GPS locations but I can't upload it to my Uno R3, I get a "data section exceeds available space in board - Global variables use 3030 bytes (147%) of dynamic memory, ...
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1answer
37 views

Can I configure an Arduino via NFC using PN532 with an iPhone as the source?

It seems clear that Apple has intentionally limited the possibilities with NFC, so I understand that I'm going against the grain here. However, I need to support Android and Apple for my device setup, ...
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HTTPClient works with localhost but not server

I started to work with HTTPClient and the WiFly library to connect to an SSID and then send POST data to a server. When I was sending the data to my localhost, it was working on localhost, but when ...
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How can I generate interrupt with negative phase shift in Arduino UNO?

I have a 20kHz source V(source) below which I cannot control and need an output V(out) from it which is leading the source. So after the first pulse the waveforms will be as follows: So V(out) will ...
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1answer
71 views

Whats common practice when using more components than there are pins?

I have a project where I want to use several motors (servo and stepper) which are activated with an RFID and show info on a display. What’s common practice or a smart way to get past such limitations?
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PWM and attachInterrupts issues

I'm trying to control the speed of a DC current motor with PWM. I use an arduino UNO to send PWM signal to a mosfet Velleman vma411 to change the average tension of a my motor which is wired to ...
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1answer
35 views

Power to triac dimmer and arduino uno

I am building 2 channel triac dimmer to control led strip lights in my pantry. Have 4 channel Krida module (just use two, I guess) and Uno. Have had some success with the triacDimmer library ...
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How to detect DTMF signal with Arduino

I'm able to detect a DTMF tone with the library https://github.com/Adrianotiger/phoneDTMF and code example: #include <PhoneDTMF.h> PhoneDTMF dtmf = PhoneDTMF(); void setup() { Serial.begin(...
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1answer
50 views

Breathing LEDs on single PWM pin?

I'm doing a project which is essentially a lighted cube, that communicates status through different colors, where I get this ides [it][1] (having code). So when the light goes below a certain level it ...
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1answer
39 views

'D1' was not declared in this scope; did you mean 'y1'?

Even though i am mentioning everything in the beginning then too m getting out of scope error. Code Reference :- https://noisycarlos.com/project/how-to-turn-your-computer-on-and-off-remotely/ I dont ...
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2answers
70 views

How to limit backlight LED current in 16x2 LCD

I'm getting the error "Current through backlight led is 23.7 kA, while maximum is 20.0 mA". What am I doing wrong? #include <LiquidCrystal.h> LiquidCrystal lcd(1, 2, 4, 5, 6, 7); ...
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Why can't I upload a programm to Uno R3 [duplicate]

I instaled driver and Uno is communicating with Win7 laptop via USB. But when I try to upload the Open Theremin software, after a while, I get this message: Arduino: 1.8.19 (Windows 7), Board: "...
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1answer
30 views

How to transmit DTMF signal to Arduino

I'm trying to read an incoming DTMF signal through the A0 input pin. I want to do this programmatically and not with the MT8870 module. This library (https://github.com/Adrianotiger/phoneDTMF) is ...
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2answers
65 views

Why analogRead's value decreases when I decrease the value of resistor?(I use digitalWrite(high) to positive terminal of resistor)

Basically, my circuit contains only 1 resistor(like the basic LED circuit). I tried to know what is the actual voltage of digitalWrite(High). I don't understand why the value of analogRead does not ...
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1answer
54 views

servo motor and l298n motor driver doesn't work together with esp32

so basically I am using 4 servo motors for our robotic arm and 1 l298n motor driver for 2 motor drive for base of the arm. when I individually tested robotic arm and controlled 4 servo motors, it ...
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31 views

I am trying to use Arduino Uno as a hid device to login Windows but I cannot use Modifier keys to Lock Windows

uint8_t buf[8] = { 0 }; #include <SPI.h> #include <MFRC522.h> // RFID library #define SS_PIN 10 //RX slave select #define RST_PIN 9 int gled = 7; // optional int rled = 4;// optional ...
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20 views

How to use the Arduino Uno as usbasp to program any AVR command line? [duplicate]

I need an usbasp which costs 365 bucks or 4 USD in my local stores.But I saw a Youtube video where a guy was teaching how we could use Arduino Uno as usbasp to program any AVR ic without usbasp. ...
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64 views

SMS with Uno in 2022

I'm trying to develop a simple sensor-triggered SMS message to mobile service from an Uno as a learning project in North America. I initially thought that it might be wise to purchase a GSM/3G ...
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1answer
62 views

Why do I get different times when using analogRead() inside while loop?

I have the following code which checks the latency of another board. int triggerPin = 13; int dataPin = 9; int ejectorPin = A0; unsigned long t_start = 0; unsigned long t_end = 0; ...
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1answer
58 views

Serial hangs on Arduino-Uno

I'm having issues with Arduino and RPI3 serial communication, it'll become unresponsive after a little time. Tried increasing BAUD rate and same issue, also happens on Windows as well so RPI is not at ...
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0answers
42 views

How I could calculate speed of a DC motor using encoder? [closed]

I am trying to calculate the speed of a DC motor using Encoder I used these components (MG513 DC-MOTOR with Encoder, Cytron 3A 4-16V Dual Channel DC Motor Driver and arduino Uno. When I roll the motor ...
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2answers
62 views

How to address arbitray leds (WS2812B) in an already defined leds array?

I want to address the first and last three pixels of a 9 pixel strip and apply a gradient to them using FastLED. I can successfully address them but the colors displayed are not correct. Is there ...
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1answer
64 views

Can I use STL on an Arduino Uno?

I started using an Arduino Uno days ago. I'm an experienced C++ dev and I'm kind of confused. Is the Arduino compiler different than a C++ one? What C++ version does Aruidno Uno use? Why it doesn't it ...
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72 views

Send/receive a hex with serial I/O board

I'm trying to get an Uno to communicate with an I/O board via serial (pins 0 & 1). The I/O board is normally sent '00 5A 58 00 07 00 00 00 B9' to read input status. The board replies with '00 5A ...
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1answer
62 views

i am tying to make a automated parking lot with a gate, sensor, button, keypad, how can i time how long has each car spent inside?

the project requires a automated parking lot, I have been able to connect and function the sensor and button for exit and enter, and the led(red lights when parking is full, green when there is spots)....
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1answer
51 views

How does Arduino Servo.h library manage to output PWM when a Servo motor is connected to a non-PWM pin? [duplicate]

While learning more about Servos, the main thing i have learned is that, Servos (SG90) need PWM signal with the frequency of 50Hz. And the duty cycle of the frequency is used to rotate the angle of ...
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0answers
35 views

Relay switch problem: Arduino Nano with a 312 PIR sensor

I am working with a 312 PIR sensor with an Arduino Uno Nano. When sensing motion Port 13 goes High for Time_A (10 minutes). If I then press a push button on the Arduino board it takes Port D2 LOW, ...
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1answer
59 views

Blinking a led using assembly language at different frequencies using two push buttons

I want to blink a led using assembly language and arduino I want the circuit to have a normal state of 5 hz blinking frequency Then use two push buttons to increase or decrease the blinking frequency ...
2
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1answer
52 views

Doubt in coding part in blink without delay

Code 1 (here unsigned long currentmillis = millis() is in loop area): const int LED = 2; unsigned long previousmillis = 0 ; const long delaytime = 1500; int ledstate = HIGH; void setup() { pinMode(...
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23 views

TdsValue showing over 700 ppm on plain tap water

i am a newcomer on arduino. currently trying to build an automated hydroponic solution adjuster. the setup is comprised of ph sensor, tds sensor, thermo sensor, 4 channel 5v relay, 2 pcs of 12v relay. ...
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41 views

PCA9685 - Hardware problem with diode?

I'm working on a project, where I need to run several high-torque servos. For that I bought come of these PCA9685 boards. I hooked everything up with my arduino and connected an external 5V - max 3A ...
2
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2answers
113 views

Arduino fade in/out 5 leds circuit acting wierd

I have a simple arduino project with 5 leds, the project should start with led 1 fade through 50 millisec to reach full brightness, then led 2 and so on until led 5 then turn them all off and loop. ...
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1answer
62 views

How can I get an external program to change values inside the Arduino C++ code? [closed]

How can I get some constantly changing values from a separate C++ program entered and uploaded into the Arduino? I notice when I upload code to the Arduino in the IDE it takes about a second to start ...
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2answers
44 views

reading strings from multiple Arduinos

So I have 5 Nanos all trying to crack a password, the idea is each one has one fifth of the list so they can test 5 at a time, then when it is found, I want it to be displayed on a screen I have, the ...
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1answer
36 views

arduino 28BYJ-48 stepper only whining, not rotating

Edit, this question has been answered in the comments by chrisl, and also after retesting the code with delay() which showed I forgot to update my lastupdate variable(eerst), I have answered it in the ...
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0answers
27 views

Grove - Mech Keycap counter

I am using Grove - Mech Keycap as a counter but if I continue pressing the keycap the counter continues to run. Any idea how to program it to increase counter by one only after releasing and pressing ...
3
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1answer
598 views

Why do we add delay when using ultrasonic sensors?

I'm a beginner in Arduino and recently i got myself an Ultrasonic sensor (HC-SR04). I looked up tutorials on how to measure distance with the sensor and the code I'm using is: const int trigPin = 8; ...
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0answers
45 views

Sending an Array using nRF24L01

im currently trying to setup a wireless Controller using 2 Arduinos that communicate with 2 nRF24L01 Modules. Unfortunately one Arduino died while testing something and therefore I can't test if the ...
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0answers
42 views

HC-05 Bluetooth module; two serial ports, COM4 and COM5

I'm learning how to use the Arduino HC-05 Bluetooth module. After pairing to it with my laptop I saw that I was getting two serial links, COM4 and COM5, as can be seen from the picture below. On COM4 ...
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0answers
78 views

220v lightbulb gradual dimmer

I am trying to turn my incandescent bulb gradually,say its brightness should go from zero to 100% in 10 mins. In doing so I found the following code and it works well but it's not as gradual as I ...

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