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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3
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1answer
4k 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 ...
0
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0answers
28 views

Weirdest behaviour with arduino and bootloaders for GPS [duplicate]

I have an EM408 GPS and an Arduino Duemilanove with an ATMega328. I have the following code to talk to the GPS and get raw data: #include <SoftwareSerial.h> SoftwareSerial GPS = SoftwareSerial(...
9
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2answers
884 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 ...
17
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2answers
42k 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 ...
0
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2answers
847 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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1answer
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 ...
1
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1answer
150 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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2answers
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 ...
12
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2answers
2k 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?) ...
7
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1answer
3k 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 ...
3
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1answer
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 ...
4
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3answers
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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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3answers
249 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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1answer
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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2answers
223 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 ...
6
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2answers
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 ...
0
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2answers
485 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 ...
3
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1answer
437 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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2answers
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 ...
1
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1answer
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 ...
22
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3answers
109k 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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0answers
40 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
3
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1answer
682 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 ...
3
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1answer
868 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 ...
4
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1answer
606 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 ...
1
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1answer
934 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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1answer
330 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 ...
0
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1answer
753 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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1answer
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 ...
7
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2answers
4k 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 ...
-1
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1answer
551 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, ...
7
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2answers
2k views

Convert a Bitstring into an integer value

I have got a String filled up with 0 and 1 and would like to get an Integer out of it: String bitString = ""; int Number; int tmp; bitString = ""; for (i=1;i<=10;i++) { tmp= analogRead (...
0
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1answer
2k views

Adafruit motor shield + Adafruit stepper not working

I have the Adafruit Motor Shield V2 and an Adafruit stepper motor. I have not soldered the shield onto the Arduino (which is an Uno) yet because I don't want to make anything permanent yet. I have the ...
5
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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 ...
2
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3answers
5k views

Solar Tracker Code - how to limit steppers to max & min angle?

a couple of friends and i are working on a double axis solar tracker with a Adafruit Motor-shield V2 and 2x Adafruit bipolar stepper motors (200/rev). We got the following code so far but are stuck ...
1
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1answer
1k views

Calculating location with 4 piezo's

i've got the following problem i'd like to get solved and i'm breaking my head, so please help! I have a rectangle with the following size 40 cm * 50 cm. On each corner of this rectangle I placed a ...
5
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2answers
1k views

Formula / calculation of the function random() / randomSeed()

In which file can I find the calculation that is called with random()? If it is not too much could you also post the content in your answer? I am using an Arduino Uno and its standard IDE. I found ...
21
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1answer
60k views

Reset an Arduino Uno in code

Is it possible to reset an Arduino (i.e., to reboot it) from code (i.e from the sketch itself)? I know that is possible with a special circuit but is there a chance to make it just with code? Below ...
-1
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1answer
215 views

How Server request happens?

Can somebody explain the below code, like how the server understands, how the request goes to the server from the below code. if (client.connect(server, port)) { client.print("GET /abc.txt"); ...
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1answer
3k views

Setting up the MMA8452 to trigger interrupt

I am working with the MMA8452q accelerometer by Freescale. I am trying to set it up to be in low power mode, to go to sleep when no motion has happened, and to wake up due to motion being detected ...
1
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1answer
352 views

digital pin's current limit, ohm's law and DC motor

A digital pin's output voltage on an UNO board is 5V, which is equal to the output from the VCC. I read that the DC current limits of those pins are 40mA and 200mA respectively, and that a higher ...
0
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1answer
1k views

SMS in modem's memory

I am working on SMS communication with my phone and Arduino. My intension is simple. When somebody send an SMS, the Arduino should read a text file located on my server and forward the content to the ...
13
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4answers
27k views

What's the deal with Uno's pin 13 LED?

(I have a Sparkfun RedBoard, but this question seems to apply to R3 Unos and Uno-compatible boards.) As I was building the first circuit in my SIK guidebook (add a resistor, LED, hook it up and make ...
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1answer
444 views

Receive SMS example gives me a garbage values

When I run my Receive SMS example code, By default every time I get the same thing.I am trying to send sms to my sim card present in the Arduino GSM shield. I don't want this message. How to solve ...
1
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1answer
2k views

GSM and GPS shield pin conflict

I have an Arduino GSM shield and I plan to purchase an Adafruit GPS shield. The GPS module uses Pin 7 & 8 for Rx and Tx, but the GSM shield uses Pin 7 for Modem Reset. Will the overlap on pin 7 ...
3
votes
1answer
3k views

How to read a Text file from server and store to a separate variable?

I am working on reading a text file from the server, using http://arduino.cc/en/Reference/GSMClientConnected. It gives me this code: char path[]="/asciilogo.txt" I want to store only the contents ...
5
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1answer
367 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 ...
5
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2answers
17k views

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 ...
1
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2answers
569 views

Figuring out some numbers for a mini pump

I'm just now getting into electronics (I don't know why I waited so long) and I'm just figuring out some stuff. I picked up an Arduino kit from Vilros.com and a few other parts for my project. I'm ...
1
vote
3answers
4k views

client.connect() fails except the first time

I am communicating with the Web server's database via Arduino GSM shield + GPRS connectivity void loop() { if (client.connect(server, port)) { ....... } else { ...