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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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22 views

How to use an Arduino as an emulator to filter signals?

What should be the Arduino code to emulate it as a 3rd order IIR filter?
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0answers
38 views

How to operate a brushless motor & ESC with an Arduino

I have recently bought two brushless motors (Brushless-300w-6-5-Wheel-Tyre-Motor-Hoverboard-Swegway-Board-Replacement-Part) along with two ESC (https://hobbyking.com/en_us/hobbyking-40a-esc-4a-ubec....
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1answer
34 views

I cannot compile the Arduino sketch when I remove the void loop function?

#include <AFMotor.h>  AF_DCMotor motor(2,MOTOR12_64KHZ); void movefor (); void moveback(); void setup() { Serial.begin(9600); Serial.println("Motor test!");` `motor....
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2answers
1k views

Run code once after programming

I'm using EEPROM to store project settings non-volatile. After reuploading the sketch to my board (over SPI via ArduinoISP), the EEPROM is reset to full 0xFFs and I have to manually do a "software ...
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1answer
37 views

How to convert a delimited string of hex numbers to an int array

I am sending a string to the Arduino via serial, I made the program that sends the data, so I can change it to anything, but for now it sends a string of hex numbers delimited by ':', so for example ...
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1answer
44 views

Proper use of the tone() function within the loop () function [duplicate]

I am trying to have my sketch run a short series of tones (melody) through a Piezo buzzer after a selection is made by the user. I am getting a compilation error with my use of the tone function in ...
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0answers
22 views

DFPlayer for Writing to SD Card

Can you use the DFPlayer to write to the SD card? Link for DFPlayer: https://www.dfrobot.com/wiki/index.php/DFPlayer_Mini_SKU:DFR0299 Here's the goal of my project. I have a button that, when pressed,...
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1answer
57 views

Arduino Code 'Bug'

I'm sharing my code.. The problem I am facing is that the code performs all the functions that are to be called except showing the MAX30100 (for heart rate) readings. I have tried this code using ...
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2answers
54 views

How to perform two tasks in one loop in Arduino?

I am trying to make a weather monitor using Arduino. I want my weather monitor to send me a message of the weather data every 5 hours using GSM sheild. Also, there is an LCD on my weather monitor ...
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0answers
14 views

Arduino Fingerprint [closed]

I have a Fingerprint based Attendance System. The LCD continuously shows 'no finger found' (as declared in case fingerprint_nofinger) after system start. It does not register a finger while I put my ...
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0answers
18 views

Are there ready made controller + screen + box available? [closed]

I'm building a power meter for my solar power system, and I'm planning to use an Arduino Uno with a 2.8" screen, and put it into a box, and then connect the current and voltage sensors through I2C. I ...
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0answers
8 views

Selection of External CT for my application

Here I have attached my ckt for my application. My application is Motor protection Relay. Based on Current sense of 3 CT tripping of relay will occur. Tripping might due to under/over/SC/Locked rotor ...
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0answers
30 views

Combining sketches

I have two codes for my to sensors and they work separately. However, I need to combine them in one program please can you help? The pulse code /* PulseSensor Starter Project and Signal Tester * ...
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2answers
49 views

Controlling 5 DC motors and 20 LEDs using an Uno (or two) [closed]

As the title says, I need to run 5 (or at least 4) DC motors (only in one direction and do not need speed either; I just need for them to be in rotation) and 20 LEDs (10 red and 10 blue. I do not need ...
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0answers
41 views

I need a random code for Arduino Uno to trigger a single relay

I am trying to get a random triggering of a single relay from an Arduino Uno. I would also ultimately like to be able to adjust the speed that the random triggering happens at. How are the times ...
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0answers
14 views

How to read multiple sensors, store into array, sort and do something with the results? [closed]

have a small project that I could use help understanding how best to move forward. I have a set of 8 batteries of different voltages and age. I’d like to read the voltages of all, assign an identifier ...
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0answers
13 views

how do i fill an array from a grayscale sensor (SKU:SEN0147)?

I'm designing a safe lock of 4 digits, but the password is in terms of colors, I have 3 colors. we are obliged to use a grayscale sensor (SKU: SEN0147). The assignment is as follows: Write a program ...
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0answers
6 views

Sparkfun load sensors and HX711 providing zero readings

I'm very new to Arduino, and I've set up a seat with four 50kg load sensors embedded inside. These are connected to a load cell combinator, which is connected to a load cell amp using jumper wires. ...
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1answer
46 views

How do I fill an empty array with the values from a sensor and compare it to another given array I filled before

I'm designing a safe lock of 4 digits, but the password is in terms of colors, I have 3 colors. we are obliged to use a grayscale sensor (SKU: SEN0147). The assignment is as follows: Write a program ...
0
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2answers
24 views

Arduino library redeclaration error

This is my first time here and I hope someone can be of help! I'll try to keep it as concise as possible. So I have two sensors/modules, 1 is an LCD screen from elecrow and another is the DS1307. ...
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0answers
14 views

How to connect to Arduino with old L293D Motor Driver

How to connect the below motor controller to the Arduino Uno board. I am new to this field. I haven't seen this type of motor controller in any tutorials. Two motors and input battery points I have ...
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2answers
31 views

Storing hash values from SHA256

I am using this code and I can not save the output of the hash function to an array of char. Can you help me how to do that? #include "sha256.h" #include <Arduino.h> #include "./printf.h" ...
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0answers
37 views

expected unqualified-id before numeric constant [on hold]

I have an obligator new here question. Ive got a hand full of sensor that im trying to monitor for some home automation. But i get this strange error at the front. Its compiled and ran dozens of ...
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0answers
17 views

Ethernet Shield Can't Connect To Server Using Access Point [closed]

I'm using Arduino Uno for a school project, and it uses an Ethernet Shield to send a request to a server. When I connect the Shield with a router, it works fine, it obtains an IP via DHCP, and sends ...
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0answers
22 views

LCD displays weird characters

I have connected the LCD by the 3 wire method using the LiquidCrystal595 library+74HC595 register shift; sometimes "hello world" is displayed but other times the LCD displays weird characters. How to ...
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1answer
33 views

Does Arduino Uno come with Virtual Pin support?

I want to recieve Data with Virtuino from my Arduino Uno 3 (Ethernet Shield) via Ethernet. Does Arduino Uno 3 support virtual pin? If so - is there a link with the Syntax I need? Thank you very much
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1answer
35 views

Question on a car kit I bought

recently bought an UNIROI Smart Car kit. (UNIROI Smart Robot Car Kit Arduino Robot Kit with 4 Wheel Drive, Arduino UNO R3 Board, Ultrasonic Sensor, Infrared Tracking Module (No Welding Required) https:...
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1answer
40 views

DHT 11 temp. And hum. Sensor always 0 values

I am trying to get my DHT 11 from the official arduino store to work (https://store.arduino.cc/grove-temperature-humidity-sensor). I am following this guide right here: http://wiki.seeedstudio.com/...
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0answers
32 views

Multiple Atmega328p wired communication

I am using multiple ATMEGA328Ps (4 ATMEGA328P) (OR Arduino Unos). The distance between two farthest ATMEGAs is 14 meters (One is Master Device and Other is Node), and other 3 are connected to each ...
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0answers
15 views

Arduino Uno Force-Sensitive Resistor

Would any one know how many Force-Sensitive Resistors that a Arduino Uno can handle being hooked up to at one time?
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0answers
38 views

Using SoftwareSerial on a Wemos D1 to get data from a GPS Shield

I am trying to use a Wemos D1 R2 to connect to my NEO-6M GPS module. I am able to make the module work fine with an Arduino UNO. I'm having significant trouble with the D1. Based upon other posts I ...
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1answer
53 views

Oscillating Output from Arduino Pins when not in use, why? [duplicate]

I have A1 set to be an input, have the program read it, and then print to the serial monitor. My question is, when the circuit is not receiving power, but is grounded, and is still connected to A1, ...
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3answers
21 views

Number of cycle depending on the number and type of statements

I did this little experiment to count the number of cycles per second in two different configurations: 1-The variable a is initialized at zero and incremented by one each cycle of the loop. -The ...
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0answers
30 views

How to use official ThingSpeak library with Arduino and ESP8266 module [duplicate]

Well I am very new with Arduino. I want to read a data and send to ThingSpeak. Reading and sending data has no problem with AT comment at this page. But I have seen examples of official ThingSpeak ...
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0answers
14 views

Arduino not responding to code [duplicate]

My arduino gives me the following error message while uploading a code avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0xff
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1answer
16 views

Custom sleep function for Nextion

I have a Nextion 7 inch enhance type display. I have enabled sleep using thsp = 120 and thup = 1 line of code. Now display become sleep mode after 2min, if there is no any touch event. But, this ...
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1answer
69 views

Slow refresh rate on I2C OLED screen

I'm trying to create a small handheld console with 6 buttons and an I2C 0.96" OLED display: https://imgur.com/a/AKiRMWN The directional buttons use the analog pin and different resistors technique to ...
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0answers
19 views

TimerOne and Saving Data to SD Card

I'm using TimerOne.h for collecting sensor (two photocells) data with a frequency of 100 ms and saving the data to a SD card. The file only seems to save data when the computer is connected to the ...
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votes
2answers
38 views

LED not turning on with following code

LED is not turning on with the following code. Have tried multiple LED's and double checked wiring. What's wrong? Using an uno. int ldr = A1; int ldrVal = ldr; int led = 6; int lvalue = 900; void ...
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0answers
23 views

I have tried to upload a sketch through the Arduino IDE to my ESP-01S but cannot upload

esptool v0.4.13-1-gf80ae31 - (c) 2014 Ch. Klippel <ck@atelier-klippel.de> setting board to ck setting baudrate from 115200 to 57600 setting port from COM1 to COM6 setting address from ...
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0answers
45 views

Arduino UNO bricked?

How can I figure out, if an Arduino UNO is defect? Have on, which I can't upload sketches to. It's not working on Windows, even on Linux. Everytime the following warning appears: avrdude: stk500_cmd(...
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1answer
33 views

Is every Arduino comes with onboard compass?

The doubt was came in mind after seeing Arduino documentation. I have to turn my Arduino uno robot 20 degrees without using encoders. So I surfed on Internet for how can I do that. Interestingly I ...
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votes
1answer
35 views

NPN sensor to Arduino

I have a beam sensor providing NPN and also PNP output. It as 4 wires and works on 24V. I hooked the brown(+) and blue(-) to a small 24V power supply and the sensor is working!!! Yeah! Now I would ...
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votes
1answer
23 views

Which is a better? GPRS SIM800L or GPRS SIM900?

I will implementate the GPRS technologity in my Arduino project, but before buy the module, I want to know which is a better. If GPRS SIM800L or GPRS SIM900? My needs are send JSON array through POST ...
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2answers
188 views

AnalogRead value constant for a varying voltage (for LED brightness variation)

Having the 11~ pin on OUTPUT mode that delivers a varying voltage (from 0 to 5 : 0 to 255). and the A0 pin on INPUT mode to read the voltage, I find that the value read by A0 being either 0 or 1016 ...
5
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2answers
1k views

Simple multiplication bug

Executing the following code always gives -511 as a result, I performed many tests, and it seems that results are correct from 0 * 0 to 181 * 181, beyond that, results are abnormal, I tried many types ...
-1
votes
1answer
28 views

How to disable the button if the stocks of my items is already 0 already [closed]

#include <Servo.h> const int coinpin = 2; const int buttonPin = 5; const int buttonPin1 = 6; int biogesicamount = 1; // Variables volatile int credits = 0; int buttonState = 0; const int ...
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1answer
16 views

Conveyor and Counter Project

I am new to Arduino and looking for advice if Arduino is the right microcontroller for this project. My project is quite simple, I want to build 3 conveyors using 3 DC motors. At the end of each ...
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2answers
49 views

How to print not enough credits if the credits is not sufficient

The problem of my code is in the serial monitor it print the not enough credits even i did not pressed the button. The output that i want is it must be print not enough credits when i pressed the ...
0
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1answer
24 views

Can't Interface SIM900a With Arduino Uno

I've got the following module of SIM900a. My connections are: VCC -> External 5 Volt 1.5 Amp Supply GND -> Common GND TX -> Arduino RX (Pin 0) RX -> Arduino TX (Pin 1) I hear a ring ...