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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.

28
votes
2answers
9k views

Arduino USB Power vs External Power Supply

Why is the Arduino able to accept ~5V from the USB, but requires a min of 7V when using an external power supply?
7
votes
1answer
759 views

Can I program a 3.3v chip on a 5v board?

I bought a Gertboard a while ago, and one of the features it has on-board is an ATMega328 (DIP). However, since the Gertboard is designed for use with the Raspberry Pi, it only operates at 3.3v, so ...
3
votes
2answers
164 views

PROGMEM char* mangled text

I wrote a program using PROGMEM for massive string arrays. One of the arrays worked, but when I added the second one, the serial output only puts out "th". Pastebin Code: http://pastebin.com/9U7QZQKn
0
votes
1answer
127 views

Unrecognizable Message From PROGMEM char*

I'm using a PROGMEM char* to store a massive array. When I try to print a certain part of the array, the message comes out mangled. How do I fix this? The output should be "Poliwag", but it comes out ...
0
votes
3answers
122 views

Arduino Not Responding During Program

I got an Arduino Uno to play around with, and started to actually dive in. During a program that I am writing for a friend, it suddenly stopped outputting to the serial monitor. When I comment out the ...
7
votes
2answers
16k views

3.3V, 5V and 9V pins on Arduino

On my Arduino Uno R3 and Arduino Mega R3, there are 5V and 3.3V pins. However on this page Introduction to the Arduino Board, there is a 5V and 9V pin but no 3.3V pin. The page at Arduino: What ...
16
votes
3answers
17k views

Arduino program only works when run as root

Uploading simple sketches seems to work when I run the Arduino program as root (sudo). I would like to run it as a regular user. Has anyone faced the same problem before and fixed it? Here is what I ...
2
votes
3answers
628 views

XBee shield communication

I need to communicate between two Arduinos using XBee. I am new to XBee and hardware. The two Arduino Unos need to send a message (number) to each other and light an LED or play a sound, when they ...
10
votes
3answers
4k views

High precision timing on Arduino for serial communication

I am using an Arduino Uno to send time and voltage information over the serial port to Python to plot. However the interval timings between successive time stamps appears to be increasing over time, ...
12
votes
4answers
67k views

How do I know the sampling frequency?

I am beginning to get a bit confused about sampling rates and baudrates etc. I have this Arduino code: #include <eHealth.h> extern volatile unsigned long timer0_overflow_count; float fanalog0;...
8
votes
3answers
22k views

Arduino time keeping using millis() is not accurate or correct?

I have been using the Arduino to record some data. In my Arduino sketch I also used the millis() function so I can keep track of the time at which each value I am measuring is taken. However, I ...
1
vote
1answer
439 views

How to interface to LPG consumption meter

I have sourced an LPG consumption meter from China with pulse output. I am looking to hook the output up to an arduino to get the consumption metrics. Unfortunately there is not too much documentation ...
4
votes
1answer
3k views

How much can an Uno be overclocked?

When running the board at room temperature (20 C) without any extra cooling mechanisms added, how much can the Arduino Uno be overclocked? Also, what would I need to change/update to overclock the ...
4
votes
1answer
116 views

Have I fried my A2 port?

I'm playing around with a SparkFun Redboard (essentially, an Arduino UNO). I have a simple 5V sensor that I'd been trying to get to work with A2 and analogRead(). Nothing seemed to work. It's ...
2
votes
4answers
3k views

Arduino disconnecting at upload

This problem doesn't seen to be very common around the Arduino community. Basically, what's happening is that as soon as I click the upload button, the Arduino IDE tells me that my Arduino board is ...
5
votes
2answers
4k views

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 ...
5
votes
2answers
530 views

Webserver on Arduino

How can I run a webserver in a Arduino Uno? I want to use my Arduino to monitor things in my home such as temperature. I want to be able to access this data through the internet.
2
votes
1answer
1k views

Redirecting Arduino Serial Output to a File

I am integrating the MPU-6050 Accelerometer + Gyro sensor into a large project that contains 12 Arduino boards and 6 Raspberry Pis. At some point, I will have to load the output of my MPU-6050 sensor ...
14
votes
4answers
9k views

Is my Arduino dead or is it just its processor?

I have a problem with my Arduino. I can't upload any sketches to it (it gives me the error avrdude: verification error; content mismatch), but the LEDs are still blinking. Do you think that the whole ...
3
votes
3answers
790 views

Build Infrared Camera Remote

I wish to build a remote for my Camera i.e Sony NEX 5R. It has a built in IR receiver and has several Sony as well as aftermarket remotes provided for it. Due to my interest in Micro controller design ...
17
votes
2answers
4k views

Should all unused analog input ports be tied to ground for accurate A2D measurements?

I am using the A0 port on my Arduino Uno to read the voltage output from an LM35 temperature sensor. I observed that the reading fluctuates a lot if I leave the remaining analog input ports A1 to A5 ...
1
vote
1answer
202 views

Arduino + IMU vs ArduIMU

I am working on a UAV and we are currently exploring inertial measurement units or IMUs. The two options that we have come across are: Using an Arduino Uno and a 9 DOF IMU like this one Using an ...
23
votes
2answers
41k views

Arduino as USB HID

Is it possible to build a HID device (like a keyboard) using an Arduino uno? At the time being, I have button inputs on the Arduino giving outputs on the serial line. So, how can I transform my ...
14
votes
6answers
43k views

How do I erase the memory of the Arduino Uno?

I'm just a tinkerer learning Arduino with my son and I was surprised that when I plugged the USB cord back in to the Arduino the program was still running and I thought to myself, "it's a good thing I ...
26
votes
11answers
124k views

How can I connect to an Arduino using WiFi?

I'm working on building a solar powered, Arduino based weather station. The weather station consists of a temperature sensor and a photoresistor, and I plan to add an anemometer in the future. I would ...
0
votes
1answer
2k views

What will happen if I give my Arduino Uno more or less than 5 volts? [closed]

Will it still run on less than 5 volts? Will it break?
1
vote
3answers
11k views

Generating PWM signal 1-2 ms @ 333 Hz

I'm currently working with the Talon SR Speed Controller and it requires a specific Input PWM Signal of 1-2 ms @ 333 Hz and an input resolution of 10-bit (1024 steps). Currently I use the Servo ...
9
votes
1answer
3k views

How can a 5v Uno talk to a 3.3v Due?

I currently have an Uno (which operates at 5v), and I'm looking at buying a Due (which only operates at 3.3v). I'd like to make them communicate via Serial or SPI or similar, but presumably connecting ...
8
votes
5answers
10k views

How can an Arduino output a specific (i.e. 56 kHz) carrier frequency?

I'm working on a free space optics project to send data wirelessly between two points. To accomplish this I'm using an IR LED connected to an Arduino Uno that pulses with a 56 kHz carrier ...
2
votes
2answers
2k views

SMPTE Timecode Reader with LCD display coding question

I've managed to adapt some code from the Arduino forums to display timecode on an LCD display. What I would like some extra help with is first is there a way of defining the one_time_max etc ...
5
votes
1answer
341 views

Can I link another device to the Uno's clock?

I'm trying to use an unusual 16x2 LCD display with my Uno. As far as I know, it's an EA-X16027AR. It doesn't seem to be compatible with the HD44780 driver, which is typically used for Arduino LCD's. ...
7
votes
1answer
4k views

What are the SVG pins for on the SainSmart Uno clone?

I bought a SainSmart clone board which is compatible with the Arduino Uno R3. Alongside each of the standard IO pins, there is a row of 3 additional pins (male). They are arranged in columns, marked S,...
50
votes
7answers
106k views

How can I create multiple running threads?

Is there a way I can have multiple parts of the program running together without doing multiple things in the same code block? One thread waiting for an external device while also blinking a LED in ...
25
votes
7answers
22k views

How can I get a unique ID for all my Arduino boards?

Once you have uploaded a sketch to one of your Arduino boards, it is hard to know exactly what source code led to that sketch. Indeed, you may change the source code of your sketch on your PC without ...
2
votes
1answer
2k views

Using the Waspmote Sensor Board

Spanish company Libelium makes this pretty impressive sensor board: http://www.libelium.com/products/waspmote/sensors/ for their Waspmote series of boards. These are not meant for Arduino ...
7
votes
3answers
5k views

Is it possible to program an Arduino Pro Mini using an Arduino Uno R3?

I've recently received an Arduino Pro Mini as a gift, and I don't have an external USB programmer to program the Pro Mini. However, I do own an Arduino Uno R3, and I think it would be possible because ...
17
votes
2answers
21k views

Why do some pins have a different PWM frequency?

According to the Arduino reference for analogWrite(), the PWM frequency on most pins is ~490 Hz. However, it's ~980 Hz for pins 5 and 6 on the Uno, and for pins 3 and 11 on the Leonardo. Why are ...
16
votes
2answers
21k views

What happens when I call exit() from my program?

In either of setup or loop, if I were to add an exit(0) call, where would control be passed to? What would the next state of the microcontroller be? Would it stop execution and power down? I am using ...
13
votes
5answers
4k views

How to connect two Arduino without shields?

I'm planning an Arduino system that consists of several Arduino boards. The maximum distance between the boards is about 50 meters. I want to send basic data between these, like short strings or ...
15
votes
3answers
108k views

How to check my Arduino board is working or dead?

When you have a board in your hand but you don't know is it working or not, how to verify if it's working or dead?
12
votes
2answers
9k views

What is the difference between the revisions of the Arduino Uno board?

There are three different revisions of the Arduino Uno. What changed in each revision?
23
votes
2answers
36k views

What are the AREF, IOREF, and the unlabeled pin next to IOREF on the Uno R3?

There are some pins on the Arduino which I haven't been able to find out anything about: IOREF AREF An unlabeled one next to IOREF What are they?
5
votes
1answer
526 views

Is my ATmega broken, and would replacing it with another break that one, too?

I was communicating between my computer and my Arduino Uno R3 through Bluetooth using this Bluetooth module. The connector I use has a red wire where it connects to GND, and a black wire where it ...
49
votes
13answers
34k views

Is there a way to have more than 14 Output pins on arduino?

Is it possible to have more than 14 output pins on the Arduino, I am working on a project in which I need to light up several LEDs individually. I only have an Arduino Uno, and I don't want to get a ...
9
votes
2answers
13k views

Is there a limit on how much current a pin can sink?

I've been experimenting with an 8x8 LED matrix controlled by an Arduino Uno. As I think is typical, the matrix uses a common anode for each row, and a common cathode for each column. At the moment, ...
17
votes
2answers
7k views

Why can't I upload a sketch while other components/devices are connected to my Uno?

I wanted to make a fairly simple circuit which would flash a series of LEDs in sequence, using my Arduino Uno (more specifically, a SainSmart clone). I wrote my sketch and it compiled fine. After that,...
17
votes
2answers
2k views

Does Arduino Uno R3 require cooling in a closure?

I was looking at getting an enclosure to house my Arduino Uno R3, but I'm not sure if I should also attach a fan. Does anyone have experience with this? It doesn't look like much heat is being ...
10
votes
3answers
558 views

How do I figure out if my board is approaching end of life?

I have a uno that I have been using for 3 years now. I will be using it again in a rather critical project in which failure on the part of the board could be rather expensive and dangerous. So, I ...
9
votes
2answers
693 views

Arduino Uno R2 and Ethernet Shield R3 compatibility

I bought an Ethernet Shield R3 for my Arduino Uno R2, but since R3 has extra pins it does not fit. Can I use the shield? Should I cut off the extra pins. What do I need to do to make it work?
1
vote
2answers
1k views

How do I communicate with the Uno using R through RStudio? [closed]

I am working on a real time application which is recording sensor data continuously. I need to process the data in realtime using R. Is there a way to connect and communicate with the uno board ...