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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Voice receiver arduino

I have the following situation. I would like to develop a bracelet prototype that identifies when a person is on the go and also issue a question to the person for that bracelet and get an ...
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Arduino Uno + cc3000 breakout board - read DOM instead of HTML

Is there a way to make the CC3000 read the DOM of a website instead of the html on the file. I'm using the WebClient file which works fine and prints the html of the webpage, but the website I'm ...
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can I use Arduino cuurent-shield-sensor to measure very small voltage?

I want to measure very small voltage in small Range -100/+100 mv from a circuit, can Arduino-shield ACS712 (max471) do that direkt ?
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Wifi Data Logger without Delay

I am really new to Arduino so please bear with me. I am running an Arduino Uno with several sensors to capture some data related to a fish tank. Here is basically what it does: Capture data (light, ...
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How to display a number using SevSeg library on 4 digit 7 segment LED display

I am getting error with this. It is displaying those segments which are not to be displayed, i.e., 3.141 is dark and other segments are red. #include "SevSeg.h" SevSeg sevseg; //Initiate a seven ...
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measure very small ( negative and positve ) Voltage with Arduino

How can I measure Voltage in Range -100mv to +100mv with Arduino , Is that an Arduino-shield can do that ?
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1k views

ESP8266 with Arduino Uno - Problem with AT+CIPSEND

The strange fact that we are facing is, the AT command is now accepting the URL and parameters provided (earlier we were coming across "Error: 400 Bad Request"), but the URL is NOT HIT even after \n ...
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912 views

Storing latitude and longitude floats as chars with specified precision

I am receiving lat and long data from a GPS and want to store these numbers in the middle of a sequence of chars. E.g. lat = -23.123456 long = 135.123456 I am after something like "Your coordinates ...
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646 views

How to communicate with GPS SIM900a without Serial Monitor

I am fairly new to Arduino. I was working on a project where I use a GSM SIM900a modem interfaced with an Arduino. The AT commands are sent via the Arduino to the GSM Modem. The problem, however, is ...
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275 views

generate two phase-shifted PWM pulses triggered by frequency-divided external signal with Arduino uno?

I have a 4kHz pulse as trigger and I need two phase-shifted PWM output with divided frequency from arduino uno. Now I've managed one PWM output using the following code: int cnt = 0; void setup() { ...
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Charge lipo battery while using

I have a system that uses Arduino and some modules. The system needs 5v dc power with 3A current at maximum(The system needs 3A current for some seconds every 5 minutes and after that the current will ...
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31 views

Two flow sensors, one ESP32, LCD and/or Arduino

I want to build a flow meter but the Gal/Min rating of something like this flow meter is too low. I am thinking of strapping two side by side with suitable plenums for In and Out. I have found some ...
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17 views

How to Work Two Linear Actuator Synchronously by Using Arduino and VNH5019 Motor Driver?

I am newbie and I want to build a project that contains two linear actuator that move synchronously. Two of them will lift up and down at same time. I use arduino mega and VNH5019 motor driver. I have ...
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536 views

Why do the LEDs visibly flicker?

The aim of the project was to be able to show two "kinds" of LEDs in a 8x8 single color LED matrix. I used a MAX7219 chip to drive the LEDs using my Arduino UNO R3 as the driver (with the usual ...
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Stable frequency generation

I'm trying to work out the best way to generate a stable frequency with my Uno R3 I'm using interrupts to generate an approximately 40KHz frequency which drives some ICs/MOSFETs to effectively ...
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94 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 ...
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Sim800 FTP Arduino

I've been unable to FTP anything using an Arduino and SIM800L. I have reduced the code as far as possible: #include <SoftwareSerial.h> //Create software serial object to communicate with ...
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303 views

Why is observed clock rate < 3MHz on Arduino Uno?

I wrote a simple loop to test the processor speed on my Arduino Uno. The numbers I'm getting are much worse than the 16MHz advertised, by a factor of ~5. Trying to figure out what I'm missing. long ...
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19 views

read and write an image through Arduino

In one of my tasks in Arduino , I should read an image from Arduino and then make it brighter with Arduino and load it in screen with serial . i've searched so much but i could not find sth useful , ...
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23 views

Pro Micro with Atmega32U4 - reset - reprogramming

i am a new user on arduino card. i have a question about "Pro Micro with Atmega32U4". - is this product programmable several times ? and the third pin (RST) - (Reset). so, does reset mean it erases ...
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11 views

Xbee communication stops after 3 or 4 transmit

I want these 2 Xbee S2C modules communicate with each other continuously. However, with my codes, they communicate just 2 or 3 times and stop. I really don't know what is the problem. My purpose is :...
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960 views

Flash String Helper object as variable

So I have a Bunch of commonly used char arrays to build commands in my library. So to preserve memory, I have them put into flash, via PROGMEM ext, typedef const char PROGMEM ProgChar; ProgChar AT[] =...
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How do i send ads1115 data over spi to master arduino

I am trying to send ADS 1115 data which is connected with Arduino mega_1 over I2C and arduino Mega_1 is connected with arduino Mega_0 over SPI. Arduino Mega_1 is act as a slave and send ADS 1115 data ...
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36k views

Sending Arduino data to MySQL using phpMyAdmin and XAMPP using Windows10

I want to send my Arduino's sensor data to a MySQL database, using XAMPP and phpMyAdmin. I have been using an ESP8266 for the wifi connection. But I am unable to send the value. And actually I have to ...
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Simple webpage serve with Arduino ethernet shield on SD card

I have been experiment with the arduino uno board from few days but can't seem to make it serve web page stored in SD card of ethernet shield. If I print the contents of the file to serial it works ...
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100 views

How can I use a transistor to “press” a button?

I have a heater remote that I want to press the buttons of with my Arduino. I am powering both the remote and Arduino from an external 5V source so both grounds are connected. Currently I have tried ...
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195 views

How to move Servo in between three positions

I want my tower pro 9g servo to start from pos=0, wait there for 1 second, then reach pos=90 wait for 1 second, then reach pos=180 and wait for 1 second. Now it goes back to pos=0 and repeats this ...
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Why is Arduino processor slow (16MHz) relative to Raspberry Pi? [on hold]

I'm curious why the common Arduinos (Uno and Mega) only have a 16 MHz processor. My first guess was that this is for cost reasons--Arduino wants to sell a cheap product under $40, and the faster ...
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26 views

12V dc fan motor rpm finding using tacho out

I need an Arduino program to find the RPM of a 12V DC fan motor. I don't want to control the speed. I only want to find the speed of the motor using tacho out.
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609 views

RFID+Fingerprint sensor code

I'm trying to create a security door system that uses an RFID and fingerprint sensor (Adafruit) to allow/deny access to a door. I have the fingerprint sensor and RFID hooked up to an LED, but the code ...
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737 views

Using Modbus-RTU with Arduino and temperature controller

I'm trying to connect with a 4 channel temperature controller using Arduino Modbus Library. This is a part of my temperature controller datasheet. It has register for read PV of each channel. I have ...
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511 views

Can I power up my Arduino and MotorShield with four AA batteries?

can I power up my Arduino UNO with four AA batteries? It's about 6V, will my arduino burn? And, if I power my Arduino, I have to power my Motor Shield too or not? I want to make line follower. I have ...
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35 views

can I check if why my motor isn't working?

I am currently using the arduino Uno connected with L298N(green pcb) connected to a dc motor rated 12V. I provided dedicated 12v power supply to the dc motor and the arduino board's power is supplied ...
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11k views

HTTP post request in JSON Format using SIM900 module

I tried to send HTTP post requests to a server in JSON Format using a SIM900 module. But the code is not posting the data. While posting the data I'm getting the error response while initializing the ...
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DC Motor speed control by using pwm

I am using Arduino Uno, and MPU6050(3 axis imu sensors), not gate, and L298 dc motor drive. My algorithm is very easy. Receive an angle how the balancing robot is tilt. Decision speed of motors by ...
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i2c Connection for MCP4725(Dac) with Esp8266 wemos d1 mini

------------ This question has been edited ------------ note: Dac and Adc is12bits my problem : I use two ESP. Using esp1, I read the Adc amount of the alternating signal (ECG) and send it to esp2 ...
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Remote Arduinos polling a master Ardrino over ethernet/wifi

I'm setting up a "Panic Button" for our Front Office. The concept is to have a master Arduino with the button and 4 other Arduinos with Strobes and/or alarms to alert the rest of the staff. The bells ...
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17 views

SD Card store struct: force big-endian / little-endian?

Following MAJENKO's tutorial on sd card file optimization and data integrity, can I force the SDCard to read and write in either big-endian or little-endian? I need this in order to maintain backup ...
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33 views

Arduino Ultrasonic Sensor and LCD - Help Needed-

I just recently purchased an Arduino Uno 3 and I wanted to make an ultrasonic distance sensor that outputs the readings to a 16x2 LCD. I followed this guide: http://www.mertarduino.com/using-...
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SIM800L HTTP request is not reliable

I have a question regarding SIM800L and HTTP GET request. I'm using this https://exploreembedded.com/wiki/Setting_up_GPRS_with_SIM800L simple code to communicate with SIM800l with AT commands. To ...
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56 views

how to interrupt the loop function and restart it?

I have a project with some NeoPixels and other LEDs and an Arduino UNO. Once switched on, the defaultLEDAnimation with colors and blinking, etc. starts. I want to trigger some other animations, so I ...
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Can you use 2 motor driver(l298n) and an nrf24l01 in an Arduino UNO? [on hold]

Can I use an nrf24l01 (external antenna) and 2 motor drivers (l298n) to control 6 motors, 4 of which in one driver to control movement (forward/backward) 1 to steer the car and 1 for a flipper? Could ...
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45 views

How to program micro chips directly with USB

Is it possible to program chips like the Arduino uno's Atmega328P directly with USB serial from your computer? Where can i find information on the protocols/standards to do such a thing? More ...
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Why do we need this resistor? [duplicate]

What is the purpose of it and on what bases its value is calcuated in ohms ?
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Can connect to esp8266 AP which is connected to Arduino UNO but no response

I am new to arduino and am trying to connect the esp8266 to arduino UNO and send commands to the arduino using an android phone. I have double, triple checked the connections and I am sure they are ...
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Problem with multi-client ASCII text parser (TCP)

I have been having a heck of a time getting my Arduino Uno Rev2 application to work as intended, which is to parse commands from multiple clients sending in ASCII-based commands over WiFi in order to ...
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1answer
50 views

No potential across output of H-bridge

I’m working on a robot with a club at my school. So far, our team has an H-bridge shield (https://www.freetronics.com.au/products/hbridge-dual-channel-h-bridge-motor-driver-shield#.WwI9omh_WEc) to ...
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595 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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How can I make Arduino communication as fast as possible with minimal (if any) error?

I'm building an inverted pendulum. I have two rotary encoders and a 12V DC motor. Right now when I try to run the DC motor and change one of the rotary encoders, the rotary encoder will not print to ...
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Can I use an RF Receiver to any pin on an Arduino?

I have a project that uses a nodemcu and it includes an rf receiver, I created the pcb board already etc etc... so I've already chosen D7 (GPI013) before reading on connecting the rf receiver and ...