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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6 answers
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Is it possible to press a button from Arduino and my computer will get a key event?

My idea seems easy: I connect a button with arduino, then write some code and upload it to arduino. Then I open the notepad(or any other editor) on my computer. When I press the button, there will ...
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  • 183
3 votes
3 answers
3k views

Arduino PWM fading led

I am trying to blink an LED with PWM on Arduino. I don't know what is wrong but my LED is not fading as expected. What is wrong? I think that I have bad registers settings, but I am not sure. LED ...
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  • 133
-2 votes
1 answer
852 views

How does RXD/TXD request signal look betwen 16u2 and 328p on oscilloscope?

I have a broken Arduino Uno. The man tells that he connected power supply and USB at the same time. I got the new 16u2 (empty) chip. then asked my friend to re-solder it. He was using an air ...
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  • 111
2 votes
2 answers
3k views

Reading the rpm of multiple fans

I am trying to build a fan controller for my pc, the problem is that the example code(http://playground.arduino.cc/Main/ReadingRPM) im using utilizes interrupts. On my uno I can then only read the rpm ...
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  • 23
1 vote
1 answer
1k views

Wired serial connection between two Arduinos - do they need a common Ground (GND)?

I would like to connect two Arduinos by a serial connection. Is it sufficient to connect TX1<-->RX2 and RX1<-->TX2 or do I also need to connect the GND of the two Arduinos?
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  • 487
-1 votes
1 answer
2k views

what is the coversion details of temperature usnig lm35?

I found similar type of code in many sites for coverting analog signal lm35 to centigrade. But i can't understand that fully. So I need some help what this equation means tempC = (5.0 * tempC * 100.0)...
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  • 511
0 votes
2 answers
2k views

Problems controlling servos using proximity sensor

I've just started using Arduino and I need to make a code to simulate the behavior of a lizard, meaning that if you come close to it, it moves away from you. I'm using a "Arduino duemilanove" that my ...
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  • 101
0 votes
3 answers
2k views

Feasability of flashing Arduino UNO r3 with teensy firmware for HID (keyboard) emulation purposes

I've been working on a DIY keyboard project I have all the hardware designed and now its time for the code. For the microcontroller, I'm sort of locked into an Arduino UNO r3 as I already have it ...
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10 votes
4 answers
40k views

What is the work of pulseIn?

I have code for an ultrasonic sensor which I found from a site. Here is the code: #define trigPin 12 #define echoPin 13 void setup() { Serial.begin (9600); pinMode(trigPin, OUTPUT); pinMode(...
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  • 511
2 votes
1 answer
545 views

How does this code work?

I've found this code below, but I can't figure out how it works. Can someone explain to me the flow of the program? #include <LiquidCrystal.h> LiquidCrystal lcd(2, 3, 10, 7, 5, 4); int mem=0; ...
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0 votes
1 answer
369 views

Unable to light up all the LEDS connected to Arduino using processing

I have 3 LEDs connected to my arduino which are controlled via laptop key presses with processing. While the LEDs are able to light up when the respective buttons are pressed, i am unable to light up ...
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2 votes
2 answers
1k views

How can I reset the program on an Arduino Uno while the device isn't recognised by my computer at all?

So I've recently been playing around with my arduino uno, and today it completely refuses to communicate with my computer at all. I've tried using other cables, switched OS (Tried Windows 8.1 and ...
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  • 31
5 votes
4 answers
21k views

How to connect more than 10 sensors to Arduino uno r3

How I can connect more than 10 sensors to Arduino Uno R3? I calculated it and I can connect just 4 fire flame sensors (sensors which can find a fire (a candle, for example)) and maybe 1 ultrasonic ...
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  • 151
1 vote
1 answer
2k views

Reading text/strings via processing

I'm trying to control an led attached to my arduino via key presses on my laptop.When i hold down a key, the led should light up, and when i release the key, the led should turn off. While my code ...
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3 votes
5 answers
21k views

How to emulate an analog potentiometer with PWM

I have a piece of electronic that controls a motor. It takes power from AC power. Now there is a 10KOhm Potentiometer. The data sheet of this controller says that the control signal is 10Vcc. Here's ...
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  • 451
0 votes
1 answer
6k views

Problems with Dallas temperature sensor code

I have connected up my temperature sensor and I am trying to run the one wire address finder to find the address of the sensor. The problem is that when I run the code it gives me the error: 'OneWire'...
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  • 266
6 votes
2 answers
3k views

How to measure voltage with Arduino analog input

I'm totally new to Arduino and to electrodynamics in general. I'm wondering what happens if I connect my digital pin to an analog input on Arduino, and make digitalWrite and analogRead on the ...
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13 votes
5 answers
20k views

Reducing lag between the arduino and a processing sketch on my computer

I'm currently on project #14 of the Arduino project book. I'm trying to control a processing sketch on my laptop using my Arduino. This is accomplished by using a potentiometer to control the ...
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0 votes
1 answer
8k views

Keyboard/mouse libraries with UNO [duplicate]

I have an Arduino Uno Rev. 3 and I'm trying to make it so that the Arduino can send a key press / mouse action to the computer. However, these libraries are restricted to a few other versions of the ...
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0 votes
1 answer
743 views

Zigbee Relay board communication with Arduino

I have bought this wireless ZigBee relay board. I was wandering about an arduino sketch to get started, I have searched for 2 days now but with no results. What I was thinking of is to have an ...
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3 votes
1 answer
5k views

Do I need to use a resistor if I am using a potentiometer to control an LED's brightness?

I am currently tinkering with an arduino, and am using a potentiometer to change the brightness of an LED. I understand that usually, a resistor is added to the circuit to limit the current flowing ...
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9 votes
2 answers
1k views

Arduino ADC Reference Voltage if it is Battery Powered

I am looking to possibly monitor battery power to the Arduino using its ADC. This is fairly straight forward and simple (especially if using the Arduino API); however, if the battery is powering the ...
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  • 300
20 votes
2 answers
50k views

How many interrupt pins can an Uno handle?

I am looking at using a 7 channel RC receiver with the Arduino Uno R3. In the documentation, there are mentions of a maximum of 2 interrupt pins, whereas on certain other blogs I have seen mentions of ...
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  • 3,637
0 votes
2 answers
894 views

Arduino ATmega328P works but board (Uno R3) seems broken

This is the first time I'm using my Arduino. It's an Arduino UNO R3. I have two boards. One works, but the other doesn't. I changed the ATmega328P from the broken one to the good one and it works, so ...
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  • 111
1 vote
1 answer
7k views

How to use String.substring?

I have the following code in which requestLine is always empty and I can't figure out why. request contains a raw HTTP request, and I want to get the first line of the request which contains the ...
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  • 111
2 votes
1 answer
156 views

How do I avoid this error trying to connect arduino to pc with linux fedora 20

I used Arduino successfully on my old Linux Fedora 12 system. Now I have a brand new PC with Fedora 20, and have today installed Arduino on it. In my first attempt to use it I typed Arduino as follows ...
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1 vote
2 answers
5k views

CC3000 - Send GET request to an app on heroku

I'm struggling to get the CC3000 to connect to a heroku hosted app, and other examples posted online haven't turned on the light bulb quite yet for me. The gist is that I collect some temperature ...
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13 votes
2 answers
3k views

Making analog telephone calls?

How can we make the Arduino board interact with old, analog telephone, and to make phone calls? I guess it involves connecting the board to the telephone with some specific cable (how it's called?) ...
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7 votes
1 answer
4k views

Why does increasing resistance make a capacitive sensor more sensitive?

From the Capacitive Sensor Page on the Arduino website, it states the following: The capacitiveSensor method toggles a microcontroller send pin to a new state and then waits for the receive pin to ...
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3 votes
1 answer
3k views

Reset fuses on atmega328p using Arduino

I bought a few atmega328p chips but unfortunately they came with the Arduino bootloader and they are set to use the external clock. I want to reset their fuses using avrdude so I can use the internal ...
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4 votes
3 answers
2k views

Significance of the numbers used in the manual

i just bought the starter kit and am currently working my way through the examples in the book when i came across some numbers used in the manual that seems a little too specific. For example, in ...
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2 votes
3 answers
257 views

Is arduino starter kit disappearing?

It seems they stop the production of arduino starter kit (official), it's hard to find it on pro website. Is there an other very good starter kit to start ? I mean I would like to try everything on ...
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  • 101
-2 votes
1 answer
2k views

Timestamp in Arduino

int sensorArray[32] ; int selectPinZero = 8; int selectPinOne = 9; int selectPinTwo = 10; int selectpinthree=11; int Enablepin=7; int inputPinOne = 0; int inputPinTwo = 1; int sensor1; int sensor2; ...
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  • 447
1 vote
2 answers
228 views

help with input in a Simon arduino uno game

I' making a Simon game with the arduino uno. I know something is wrong with the inputs but i don't know why or how to fix it. The problem is the program takes an input and says it is correct no ...
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  • 113
6 votes
2 answers
6k views

bootloader uploading into Atmega328

Here is mine circuit. Intially i used arduino UNO directly for programming. Now i am Using atmega 328 IC for programming. I am trying to connect 32 hall sensor via Mux circut. I wanted to How to ...
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  • 447
0 votes
2 answers
557 views

Stacking shields without headers

In the project I am working on, I have a limited space with which I can work. I am using an Arduino Uno with 2 Adafruit motor shields, and when I stack them using normal, female stacking headers it is ...
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3 votes
1 answer
455 views

Setting time frame in Arduino Uno

I have built the circuit below using mux ICs. In a particular interval the respective selector pins get selected and analog signal from hall sensors are read and give a particular analog value out. ...
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  • 447
1 vote
2 answers
2k views

Error while connecting Arduino to Macbook: “serial port already in use. try quitting any programs that may be using it”

I'm trying to connect to my Arduino board through a macbook pro with mac os x 10.9.3 installed. I'm following the instructions from the arduino guide and in the connection section: " Connect the ...
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1 vote
1 answer
1k views

SoftwareSerial error

I have arduino , upon arduino I have Arduino GSM shield (Tx-2, Rx-3, Modem reset-7) and upon it, I have the Adafruit GPS Logger shield. I am trying to send sms of Latitude from the GPS Logger shield ...
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  • 389
26 votes
3 answers
124k views

What is Serial.begin(9600)?

I know that this is to initialize something: Serial.begin(9600); But I want to know what it really means?
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  • 511
1 vote
0 answers
41 views

How to communicate arduino with Matlab [duplicate]

I have been working on a project which deals with analysing data from sensors to matlab. How do i establish this communication. Please help me
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  • 11
3 votes
1 answer
769 views

To connect a simple toy circuit and trigger with an arduino?

I have a small circuit from a toy sword that has an LED and a small speaker. It was powered by a couple of small coin cells. I am trying to figure out how to connect it to my Arduino so I can trigger ...
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  • 135
3 votes
1 answer
1k views

Timer1 stops firing

I am trying to use interrupts to play notes on a speaker. Timer2 works fine, but after about 15 seconds, Timer1 stops firing for about 5 seconds, and then it comes back on. If I keep running the ...
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4 votes
1 answer
611 views

Can a PC connect to an Arduino for serial communication without installing the entire dev kit?

I'd like to send a prototype board to a friend pre-programmed and wired. Ideally they should just need to plug in the USB and connect to it over a serial COM port. With another laptop I used for ...
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  • 249
1 vote
1 answer
976 views

Unable to read text file from server

I saw the Web client Example , In the example, the server connection is initialized in setup(). But I want the server to update the text file every time. So, I need the server connection to be in ...
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  • 389
1 vote
1 answer
333 views

Detecting ball moving between IR pair and handling ambient light changes

I plan to use the SEN-00241 IR Emitter and Detector pair to detect a ping pong ball moving fast between them. I understand I could watch for voltage changes to detect this passing object, however how ...
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  • 111
0 votes
1 answer
821 views

DC-DC converter with Arduino not working

I've got a program running on the Arduino that is supposed to turn on and off a pump. currently, I am outputting the reads of the components that need to be read and it shows when the port (port 13) ...
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-2 votes
1 answer
1k views

Cheapest way to connect android device to arduino wirelessly

I'm building a simple RC car which I want to control using android phone. The phone has bluetooth and Wi-Fi. My questions is what will be the cheapest way to connect the two devices at about 50-120m ...
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  • 157
9 votes
2 answers
5k views

Use Higher Resistance Than Instructed in a Circuit

I'm following the "Get Started with Arduino" Guidebook, and I'm at the part where pulse width modulation (PWM) is discussed. The instructions say to create a simple circuit with a breadboard, red ...
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  • 93
0 votes
1 answer
607 views

How to update a text file dynamically

I have Two Arduinos, One with the help of sensors it will dynamically updates in to my server database. Other Arduino, reads the stored contents from the server database and sends sms to phones. Now, ...
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  • 389