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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How does the reset button work on the Arduino?

I'm confused about how and when to use the reset button on the Arduino. Do I simply press the button while it is on? Is it simply restarting the board or clearing the uploaded code as well? Currently ...
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RTC MCP7940M not counting up

I'm able to set a time and to read it back without any problems but it doesn’t tick up. It stays the same. Even if I restart the serial monitor and thereby resets the buffer(?). So it seems to me that ...
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847 views

Cannot compile C++11 code via Makefile

I am building my Arduino project with a makefile: BOARD_TAG = uno ARDUINO_PORT = /dev/ttyACM0 USER_LIB_PATH = /home/prakhar/dev/alfred/arduino/libraries CPPFLAGS=-x c++ -std=c++11 -Wall -...
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Does ATMega 328/2560 chips support JTAG-type programmer and hardware debugger?

As stated in www.Arduino.cc FAQ, "Can I use an Arduino board without the Arduino software? Sure. It's just an AVR development board, you can use straight AVR C or C++ (with avr-gcc and avrdude or AVR ...
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Does the tone() generates unwanted signal?

I was trying to use the tone function for another project but I found that it also generates an undesired frequency (not the harmonics above of square wave it generates) but a lower frq square wave. ...
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How to measure resistance of TFT Touchscreen

I'm using a TFT Touchscreen shield with my Arduino UNO, and I'm running "tftpaint" example by Adafruit. I've noticed that when initializing the Touchscreen object, a resistance value must be provided....
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How does Arduino IDE 'Get Board Info'?

I want my C# application to automatically select the correct COM port by way of a string equality check against a 'GetInfo'-type request to the Arduino board. I know the Arduino IDE can get info ...
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2answers
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Programmatically Change Arduino Com Port Name

I have some devices that, when I plug in, will display a unique name, usually a serial number, as opposed to "COM #" is there any way I can have my Arduino Uno (or Mega) give itself a different name ...
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3answers
453 views

Not getting proper readings on Arduino from MAP Sensor

In recent project, I have to take reading from MAP sensor. So basically, we used analog pin for this. But in my case, I don't get proper result which actually I want. When I'm taking readings through ...
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How to clear FIFO buffer on MPU6050?

my MPU6050 works very unstable , the problem is unable clear excessed FIFO buffer on MPU6050, I am using Jeff Rowberg's MPU library and according to his DMP example but without using interruptions,...
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Why bootloader sizes differs from 0.5 to 8 kilo bytes for different boards?

According to official web info bootloader sizes are 0.5, 2 and 8 kilo bytes for UNO, Pro mini and ATMega2560. I believe all three boot loaders do similar job of receiving serial link data and write to ...
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Parsing JSON on the Arduino

I'm using the ArduinoJson library. There is a great example for parsing a single JSON object in the source code. I am attempting to iterate over an array of JSON objects: #include <JsonParser.h>...
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how does serial port communication work under the hood?

im just looking for how to send/ write date to pc over serial port from arduino..vice versa. I have few Question to ask after taking so much time and couldn't figure it out myself. I hope you guys ...
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LCD scrolling down problem

I have a list of set-ups and I only have 2 rows in the lcd , I'm trying to scroll down for the moment and I'm doing this by changing the row in the setcursor function to either 0 or 1. However since ...
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4answers
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Timer2 does not work as it should

I am currently playing with Arduino timers (on UNO currently) and I am building a library that has a function that must be called every millisecond. There is plenty of code samples on Internet so I ...
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1answer
583 views

cannot convert 'bool' to 'PinStatus' for argument '2' to 'void digitalWrite(pin_size_t, PinStatus) on Arduino Uno Rev 2 Wifi not working

I am a newbie to micro controllers and struggling to figure out how to fix this issue. When using an older Arduino micro controller it works fine, but when I use a new board (Arduino Uno Rev 2 Wifi) ...
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2answers
952 views

Power on reset with arduino uno can never happen. Can this be fixed?

When an Arduino Uno is powered on, the USB chip's DTR output pin may (is, in fact) low for a while. This means that the capacitor C5 is connected from the 328p reset pin to ground. Thus, when power ...
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1answer
216 views

How well will the Arduino Uno survive in a vacuum?

Im doing some experiments with Pocketlab and Arduino, Vacuum will get to around -30inHg. I tried with my raspberry pi and it just kept dying everytime a vacuum was pulled. The only problem I can image ...
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Adding an LCD to Uno but not enough pins left

I am an absolute beginner and wanted to build a simple home automation system using DTMF module using this guide. My problem is out of 12 pins most of them are getting used in DTMF module(5) and the ...
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119 views

Is there any chance of fixing it?

I am new to arduino and robotic stuffs and I thought it would be a good idea to test circuits on my breadboard using arduino's R3 5V pin as power supply. The accident happened when I short circuited ...
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Why do my temperature sensor values become inconsistent when additional hardware is added to the board?

I have this strange problem. My TMP 36 sensor works fine when it is the only thing connected to my Arduino Uno board. The voltage measurements, and thus the temperature, are accurate and consistent. ...
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Do I need 3 voltage dividers to control ESP8266

I am buying an ESP8266 and the plan is to control it serially from an Arduino. I am going to use a voltage divider(Using a voltage divider is temporary and I know the cons of using voltage dividers). ...
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Why does an LED sometimes flash when increasing brightness?

This is admittedly a cross-post from LED fade malfunction (random flash) but I can't get an answer on the Arduino forum. I was mucking around with some very basic code and I noticed that when ...
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Multiple GSM shields on one Arduino

I am looking for a way to listen for received text messages on multiple numbers. When I came across the Arduino and its shields, I thought to myself this might be the perfect way to do just that. One ...
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1answer
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ov7670 + Sd Card + arduino

I have three devices for making a motion activated security camera system: this is the camera : LINK OV 7670 this is the SD Card module: LINK and a basic motion Sensor: PIR with 3 pin I have an ...
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151 views

In Linux, how do I get this Arduino library to work

In Linux Fedora 20 Arduino I want to use the Timer library from here, from which I have downloaded the folder Timer-master.zip, but, when I try to import it, I get the Arduino message that it cannot ...
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How to on/off light dimmer using another pin?

In recent project, I'm working with light dimmer. Let me explain with example of fan. In switch board, we have a fan switch which can able to ON/OFF our fan & FAN REGULATOR which vary speed of ...
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Sending uint16_t over I2C

How do you transmit and read a uint16_t over I2C? I'm trying to read two uint16_t values from a slave device, and I'm seeing nonsensical readings. This is the code on my slave Arduino Uno: #include ...
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Why/when to use IoT publish/subscribe protocols rather then RESTful HTTP?

I am sending data (GPS coordinates) from Arduino once a minute with HTTP POST request to REST API (in OpenShift PaaS). Data is then stored to MySQL db. Would so called "IoT" publish/subscribe ...
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1answer
2k views

Optocouplers for Arduino DCC decoder - Explain?

I am trying to make an Arduino circuit as outlined here. This is for connecting an Arduino input to a DCC system. DCC is a command control system for model railways that uses the same two wires for ...
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Disconnect Ethernet Shield

I'm trying to use the Ethernet Shield and the EasyVR (voice recognition) together. The Ethernet shield uses the same pins that the EasyVR, but the easyVR works fine if I don't call Ethernet.begin(). ...
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Capturing images from OV7670 (w/o FIFO) using Arduino Uno?

I want to capture images from my OV7670 (w/o FIFO) and send it to my PC via Wi-Fi (ESP8266) (which I know how to use) using an Arduino Uno. I have read so many blogs and threads on the internet but ...
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Random(min,max) Function only giving ~50 range no matter what the values?

I can't get the min,max range to function properly. Monitoring the serial, only gives out ~50 difference from the min. I then added truerandom.ino to try to fix, but no help. const int ledPin = 13; //...
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1answer
338 views

Powering 5V Accesories

I'm using an Uno to control NeoPixels LED strips (60 per metre). These are powered with a 5V DC supply. Now, when using USB to power the Arduino it works lovely. However I want to move the Arduino ...
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1answer
148 views

Does porting code to different MCU clock frequency affect serial baud rate?

Tried to upload my Arduino Uno sketch that writes to serial UART at 9600 baud rate onto my ATtiny2313 running at 1MHz. Not getting the signal on the ATtiny, does this have to do with my clock ...
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3answers
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Bluetooth HC-05 module returns encoded data

I have searched online, and haven't found anyone hitting this issue. Strangely my Bluetooth HC-05 is returning encoded data. I have tried using different boards - Induing, Uno, Freeduino and I have ...
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1answer
2k views

How to make XBee module interrupt/wake arduino

What I am trying to do is, to have arduino in low power mode and waking up only when a packet is received and is available to be read from the buffer. A scenario : Zigbee XBee module is not ...
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How to receive data from my server database to a variable in my Arduino?

I am learning to work with the client - server communication. I am able to communicate with my server and able to store values in the table. But I want to receive one of the specific data from the ...
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1answer
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SoftwareSerial too slow for MIDI?

I tried to use the SoftwareSerial library for MIDI (by 47 effects), but it seems I get regularly corrupted/unexpected messages. The circuit I'm using works perfectly when I connect it with the ...
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1answer
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ATmega AVR frequency measurement with timer/counter

I've been rehashing some existing libraries I found on some obscure forums to measure a frequency on digital pin 5, using the ATmega328P/ATmega2560 Timer/Counter modules and an interrupt based ...
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Explain what is meant by “Arduino core”

What is an "Arduino core"? Are there many different "Arduino cores"? such as a core that applies to LCD displays, another core that applies to servos, etc.?
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1answer
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Modbus Communication protocol for Arduino as Slave

I have an Arduino Uno board, with these components: rs-485 Modbus module shield Multiprotocol radio shield board for Arduino In addition I have a level sensor which reads either 1 when it is above ...
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How to connect new OV7670 FIFO to Arduino?

I bought a new OV7670 FIFO camera to connect to my Arduino UNO a few days ago. The picture of the cam board: I found this forum, it is nice try but it looks chaotic and confusing with about 50 pages,...
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1answer
366 views

Is the Sparkfun RedBoard pre-loaded with a blink sketch?

As soon as I plugged my brand new RedBoard (Sparkfun's Uno) into my computer, I saw the onboard LED (for pin 13) blink on and off every 1 second. This was before I even sent the first demo sketch to ...
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787 views

Understanding the relationship of Pulse and Stepper RPM

This may be a better question for the Physics StackExchange so tell me if I should move the question. I have a pretty simple script that I'm using to control the RPM of my stepper motor: void loop(){...
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My Servo Won't Sweep Smoothly

So I've tried this a few times and I always get the same issue. When I try to run the sweep example the servo goes round 180 degrees but only in steps. Anyone know a way to fix this? The servo I'm ...
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2answers
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Arduino serial port reset in Serial monitor & Python

So am I using an Arduino with a shield to gain some voltage values for an ECG. I am then plotting that data in Python. However whenever I "observe" the serial port, be that through the Arduino serial ...
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1answer
609 views

Uno with LCD acting strangely - power issue?

I've got a Uno (Elegoo UNO R3) running with - Ethernet shield (Kuman K15), - 4 relay board (Elegoo 4 Channel DC 5V Relay Module with Optocoupler ) - Matrix Orbital 2041 LCD connected via I2C (11mA ...
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2answers
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Arduino Uno as USB to Serial converter (bypass 328p)

I'm trying out computer to computer serial communication using 2 Arduino Unos (both connected to different computers). Right now, I use the Software Serial library, which redirects data from the ...
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1answer
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Can an Arduino emulate a USB mass storage device?

Question: Can I connect an Arduino's USB port to the USB port of another embedded device that is expecting a USB thumb/flash device? Or, can I connect a USB module to this embedded device, with the ...

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