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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Alternatives to Radio Transceivers

So i am creating a haunt project that needs a way of detecting when an Arduino passes it and makes that Arduino do something. the problem I'm having is that none of the transmitter and receiver that ...
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How I can populate a buffer from data read from SPI?

I have wired a Macronix MX35LF1GE4AB Flash memory into an arduino Uno using Logic Level Shifters. What I try to do with it is to dump its contents. In order to do so, I am implementing the following ...
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I need to run 2 for() loops simultaneously but I cant seem to do it without one executing, then the other after it [closed]

I'm controlling 2 servo motors but would like to adjust their variables separately, specifically their upper and lower values, and their speeds. This code is one that I had found online then ...
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How to convert serialized JSON string back to JSON object?

How to convert JSON String for example {"f0":100,"f1":100,"f2":100} It is what I get from my esp01 side from I2C communication Now I want it to get it back to my Arduino ...
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High frequency sampling with Arduino

I need to sample signals up to about 200 kHz using the Arduino as a kind of oscilloscope. I have already seen that by itself it is unable to do it, since the sample frequency is about 9.6 kHz. But ...
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Arduino HX711 load cell lots of drift

I am trying to make this 50kg load cell work with this HX711 chip. I currently have the following connections : Load cell red -> E+ Load cell black -> E- Load cell white -> A- Load cell ...
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Using IN1/ IN2 pins for PWM instead of ENA in L298N

So basically i tried providing PWM directly to the IN1/IN2 Of L298n motor driver instead of using ENA pin i got more or less the same result Im using ESP32 with 30000Hz freq for my PWM My question is ...
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3 votes
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558 views

What is the difference between Bluetooth module HC-05 and HC-42 for Arduino?

I am looking for differences between HC-05 and HC-42 Bluetooth modules for Arduino. I could not find an answer by searching google. Both products have 6 pins and accept master and slave but I could ...
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Using ESP8266 to program Arduino by serial comm

Since ESP8266 can self program on wifi, can we use it to program arduino too with the binary sent via wifi? my arduino is connected with reset+RX+TX pins and shared power. Has this been already done?
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Interval timer on Arduino: Doubt about TimerOne library

I want to synchronize a timer interrupt from a button is pressed. I want to read a button state 3 seconds later from the first pulse moment (to identify long pressed button, 3 seconds for this example)...
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Where am I going wrong in modifying Timer0 and the ISR interrupts in this example?

(Arduino) Hello I don't know where I am going wrong here, please advise. In the end I want to step a bipolar motor, HIGH/LOW, using Timer0 with OCR0A and OCR0B interrupts to adjust the motors step ...
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Connecting Common-Anode Seven Segment Display to Shift Register

I recently wired up the following ill-advised circuit: A common-anode display is wired with its cathodes connected directly to LEDs connected to ground. But the strange thing is that it worked ...
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Arduino Uno R3 not recognized by Arduino IDE on Ubuntu 21.04

Now I've been pulling my hair for two days over this one. I've tried everything. I've turned every stone, looked at every search result, and every Arduino Forums thread. The problem is that Arduino ...
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ESP8266: ESPASyncserver + client

I have project with an ESPAsyncWebServer with websockets working already. What I need to add is Client functionality to poll a site for a response. I looked at the ASyncTCP library and it has two ...
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2 votes
2 answers
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Trying to understand the bottleneck of sensor sampling rate

Lets say I have a sensor connected to Arduino Uno Rev3's I2C Bus. I am reading the sensor output and using Serial.print() to send the sensor reading back to a my laptop. I am trying to understand the ...
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3 votes
2 answers
53 views

L298N DC Motor Driver Conundrum

I am trying to control a single DC motor using a L298N DC Motor Driver. I have a 12V motor plugged into Out1 and Out2, a 7.4 volt battery wired to the 12v in and common ground, a m/m common ground ...
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Using Random() and Greater Than

Total Arduino noob, I come from a Python "background", though I barely know that, either. I'm writing a super simple script that will turn on a bulb when the random number generator ...
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I cant get a stepper motor to work with arduino UNO [duplicate]

I'm using an arduino UNO with a L2989N motor controller with a nema 17 hanpose 17h3401 stepper motor. I'm using two 9 volt batteries in series to power it. I'm sure I connected them properly but it ...
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1 vote
1 answer
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Writing Arduino code for MPXV6115V pressure sensor

I'm attempting to use an MPXV6115V pressure sensor to monitor the constant vacuum of a suction device. I haven't been able to find a library to use with this sensor. I'm very new to Arduino but I am a ...
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1 vote
1 answer
116 views

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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3 votes
1 answer
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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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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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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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1 vote
1 answer
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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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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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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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2 votes
2 answers
102 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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1 answer
67 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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1 vote
1 answer
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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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-1 votes
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'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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2 votes
2 answers
431 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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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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1 vote
2 answers
78 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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1 vote
1 answer
172 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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1 vote
0 answers
37 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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1 vote
0 answers
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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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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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1 vote
1 answer
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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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-1 votes
2 answers
93 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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0 votes
1 answer
93 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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-1 votes
1 answer
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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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2 votes
1 answer
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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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1 vote
0 answers
40 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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1 vote
1 answer
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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 ...
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2 votes
1 answer
58 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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3 votes
0 answers
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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 ...
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2 votes
2 answers
121 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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-2 votes
1 answer
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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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