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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Arduino fade in/out 5 leds circuit acting wierd

I have a simple arduino project with 5 leds, the project should start with led 1 fade through 50 millisec to reach full brightness, then led 2 and so on until led 5 then turn them all off and loop. ...
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-2 votes
1 answer
75 views

How can I get an external program to change values inside the Arduino C++ code? [closed]

How can I get some constantly changing values from a separate C++ program entered and uploaded into the Arduino? I notice when I upload code to the Arduino in the IDE it takes about a second to start ...
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2 answers
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reading strings from multiple Arduinos

So I have 5 Nanos all trying to crack a password, the idea is each one has one fifth of the list so they can test 5 at a time, then when it is found, I want it to be displayed on a screen I have, the ...
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0 votes
1 answer
217 views

arduino 28BYJ-48 stepper only whining, not rotating

Edit, this question has been answered in the comments by chrisl, and also after retesting the code with delay() which showed I forgot to update my lastupdate variable(eerst), I have answered it in the ...
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1 vote
0 answers
31 views

Grove - Mech Keycap counter

I am using Grove - Mech Keycap as a counter but if I continue pressing the keycap the counter continues to run. Any idea how to program it to increase counter by one only after releasing and pressing ...
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3 votes
1 answer
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Why do we add delay when using ultrasonic sensors?

I'm a beginner in Arduino and recently i got myself an Ultrasonic sensor (HC-SR04). I looked up tutorials on how to measure distance with the sensor and the code I'm using is: const int trigPin = 8; ...
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0 answers
101 views

HC-05 Bluetooth module; two serial ports, COM4 and COM5

I'm learning how to use the Arduino HC-05 Bluetooth module. After pairing to it with my laptop I saw that I was getting two serial links, COM4 and COM5, as can be seen from the picture below. On COM4 ...
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3 votes
0 answers
100 views

220v lightbulb gradual dimmer

I am trying to turn my incandescent bulb gradually,say its brightness should go from zero to 100% in 10 mins. In doing so I found the following code and it works well but it's not as gradual as I ...
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1 answer
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Stepper motor with microstep driver

In my project I have to control a stepper motor using arduino and microstep driver, can I control the motor so that it can move 90 degrees then stop for like a second and then move again and repeat ...
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0 votes
2 answers
49 views

Can arduino show the power drawn from its output pin on serial monitor? If yes, what code should I use?

I want to know is it possible that arduino can show how much power my prototype is drawing from arduino and if it can what would be the code for that.
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My arduino gives me several avrdude erros

For school we program an arduino with visual studio and micro visio. Since a few days ago my arduino wont run the code of the arduino. At first it didnt give any errors until i tried to upload a code ...
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-2 votes
1 answer
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How do I create a code that lets me use an array of 10 thermistors on one arduino?

I am new to programming and am trying to create an array of 10 thermistors on one arduino. So far I have found a code for Temperature Sensor Using NTC Thermistor that is only for one thermistor. How ...
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3 votes
1 answer
114 views

How to use HC-SR04 sensor to make a flowmeter?

I am somewhat familiar with Arduino and am trying to use two ultrasonic HC-SR04 modules to measure the direction of water flow inside a pipe. The sensors are kept as in the image below. The direction ...
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1 vote
1 answer
32 views

Sunfounder IR remote controller issue

I've been making a hoverboard using arduino, tinkercad and c++ (pic included). When I wired it up irl, I wired it exactly as I did in the picture (arduino UNO) However, when I tested it out, it didn't ...
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1 vote
1 answer
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Morse encoder code not working as expected on Arduino UNO [closed]

I'll start saying that I don't have much experience working with Arduino and programming in C. I have an Elegoo Arduino UNO clone. Recently I was trying to build a morse encode which converts a text ...
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  • 53
1 vote
1 answer
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Can't burn fuse bits on ATMega168 with Arduino Uno as ISP

I have an ATMega168 that I am programming via my Arduino Uno as ISP. I can burn the bootloader and transfer a hex file just fine, but I can't seem to be able to change the fuse bits. I found a lot of ...
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1 vote
1 answer
70 views

Arduino uno spi sck not working

I am trying to verify sck output on my arduino uno. I don't have oscilloscope so I loopbacked miso to sck and tried Executing int rx0=SPI.transfer(5) while printing this using Serial.printrx0) it is ...
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0 votes
1 answer
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Where does the 5v Output power on the Arduino uno come from?

I am wondering where the extra 5v output power on the Arduino uno come from. Is it directly from the atmega328 microcontroller or from the external power source (usb or 9v battery). Thanks.
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1 vote
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Problem when using Servo.h and WIre.h libraries [duplicate]

I have a project that consists of an Arduino, a NodeMCU and 2 servos. The NodeMCU is configured as master and the Arduino as slave. I have bidirectional flow of data between them. In order to receive ...
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1 vote
1 answer
45 views

Arduino Uno stops accepting command from PS3 Wireless controller?? although it remains connected!

so I was trying to control a bot wirelessly with the help of ps3 controller and USB host shield, i am using Arduino UNO as micro-controller. I was able to connect PS3 controller with Arduino and ...
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1 vote
0 answers
33 views

Possible way to interface a TFT touch panel with Arduino [duplicate]

I have a salvaged 40-pin TFT touch panel, and I am trying to see if I can control it with an Arduino. What are my chances of getting a driver for it ? I bought a RA8875 Driver Board from Adafruit, but ...
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1 vote
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servos act strangely instead of stopping/starting

I am trying to make it so that my robot rolls straight when pin 8 is high and stop when pin 8 is low, the 2 servos is constant rotation servos. instead the servos spin when the wire touches it pin ...
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0 answers
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I want my LED's to turn on for 5 sec when the Ultrasonic Sensor Activated

const int Trigger = 6; const int Echo = 7; const int LEDpin1 = 4; const int LEDpin2 = 5; const int Parameter = 400; float Time; void setup() { Serial.begin(9600); pinMode(Trigger, OUTPUT); pinMode(...
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1 vote
0 answers
42 views

Arduino UNO and PCA9685 - Problem with external power supply

I am totally desperate and hope you can help me. I've been building a project for a while where I have to control several servos. For this I bought some MG996R servos and a PCA9685 16-Channel Servo ...
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  • 161
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2 answers
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How do I connect 20 outputs and 20 inputs to an Arduino board?

I am a mechanical engineer starting my journey with Arduino, so please excuse me if I put some very generalized message. I need to sequentially operate 20 output relays, and then verify if the ...
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0 answers
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Serial communication between Python & Arduino: [duplicate]

I need to transfer information between pyton script and arduino. Data is always built like this "wheelbase:1000" wheelbase can be another word and 1000 can be another value, : is always the ...
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  • 113
1 vote
0 answers
30 views

i have problem in generating pwm in steps

Given below is my loop and it counts 1 to 250 using the push button i just added this part as this one is the main part. I want to make it in steps like one press (push button) SETS IT TO 10 OR 20 ETC....
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  • 51
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1 answer
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I have this issue on Arduino by stating that Adafruit_SSD1306_128x64_i2c_init(); was not declared in the scope, may I ask why?

I have included Adafruit_SSD1306.h file however, it still shows me error such as 'Adafruit_SSD1306_128x64_i2c_init(); was not declared in the scope' Can anyone enlighten me for this?
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1 vote
0 answers
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My port is grayed out?

Hello I have a question on why my port is grayed out when I go to upload? I’ve watched so many YouTube videos on what’s the problem and have been trying to do everything but just nothing seems to work!...
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2 votes
1 answer
127 views

Arduino data-types

(Im new to the arduino side of stackexchange). Im working on a worksheet for to begin with arduino. I have prior experiences working with arduinos, but problem is new for my field of expertise. Any ...
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1 vote
0 answers
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Arduino and PCA9685 - Suddenly stopped working

I'm using an Arduino Uno and a PCA9685 board to run 4 servos (of type MG996R). For that, I set up the following connections: SCL -> SCL SDA -> SDA Ground -> GT VCC -> 3.3V As the servos ...
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1 vote
1 answer
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Need help figuring out how to adapt a code for a Snake Game I'm trying to make. Help greatly appreciated!

first of all thanks for clicking on this post :D For the last couple of days I've been trying to test out a game for the classic nokia snake game I've found online, but I can't seem to get it to work. ...
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1 vote
0 answers
37 views

Arduino Visible Light Communication(Audio transmission)

I think this is a broad question. I'm currently implementing visible light communication with Arduino. I'm using a laser as my transmitter and LDR as my receiver. I'm able to transmit a text from one ...
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-1 votes
1 answer
46 views

UART connected device communication only works one way

As the title implies, I have two Arduino devices (Uno and Mega) connected to each other over UART (the Mega is hardware UART, the Uno is software UART); I need the Mega to send a command to the Uno, ...
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  • 63
2 votes
1 answer
150 views

How to Independently run positional and continuous servos using millis()?

I am setting up 3 servos (2 position servos and 1 '360' continuous rotational servo) with Arduino. but I failed to run these independently. It runs one after another. I wish to run it in loop ...
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1 vote
0 answers
30 views

Robotdyn esp8266 interrupt from arduino timing

I use a Robotdyn, uno+wifi r3 atmega328p+esp8266. I need to control motor speed and operate few servos. Since the uno has a single timer, I use the esp8266 pin 2 to control motor speed, while the ...
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1 vote
1 answer
77 views

LCD displays more digits than serial monitor

I am doing a BPM monitoring system. The serial monitor displays accurate BPM values ranging from 60 to 100+. But my LCD display is not accurate. Example, on the serial monitor, my bpm is about 67, but ...
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1 vote
0 answers
75 views

rfid module not working (rc522)

i brought a rfid module which is rc 522 but when i upload the code it is not reading the card even when i upload example code i have returned it 2 times and got it replaced but the same problem may i ...
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1 vote
0 answers
42 views

SIM900 AT+CCID ERROR

I have my SIM900 connected to a 12v 2A power source, I have inserted my sim card changed it to 3G/2G(autoconnect) ( I did research it to know wheteher it is possible and it turns out it is, the only ...
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2 votes
4 answers
533 views

My program is using too much memory

I work in a warehouse and I was tasked to make a device which will show the location of any product when Product ID is given. All of our product has 3 things. Product ID, Rack Number and Gap number. ...
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1 vote
0 answers
122 views

Analog UV sensor displaying incorrect values in serial monitor (GUVA-S12SD)

Using Arduino Uno and a GUVA-S12SD sensor (https://www.adafruit.com/product/1918). Here's my circuit. 5V into sensor+, GND into sensor-, A0 to sensor out. Here's my code: void setup() { Serial....
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0 votes
1 answer
300 views

HW-477 Module having VS1838B IR Sensor: Help with Pins

Ordered Universal IR Receiver and I got HW-477 module with VS1838B IR Sensor. Good thing is datasheet for VS1838B is available but not for HW-477. VS1838B pins as: Ref Signal | GND | VCC while HW-477 ...
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  • 135
1 vote
0 answers
44 views

Multiple SoftwareSerial's at the same time? [duplicate]

I need to receive some data from USB and send it to the Android device via Bluetooth. The problem is that multiple SoftwareSerials won't connect at the same time. Here is my code: SoftwareSerial ...
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1 vote
0 answers
51 views

Is there any way to export a sketch from an Arduino to my laptop? [duplicate]

I was having a sketch but I accidentally downloaded a file which was containing a virus. That virus deleted all my Arduino sketches. I uploaded a sketch into my Arduino UNO and it is still in there. ...
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1 vote
1 answer
70 views

what is the maximum number of servo motors that can be connected to a l293d motor shield?

I have a requirement in which I need to run 2 motors and 6 servos. The motors and servos won't be running simultaneously at any given time. what best can I use. I Was hoping to use l293d shield as it ...
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1 vote
2 answers
379 views

How to change brightness of LED light?

I'm trying to change the brightness of an LED light with RGB. I can change the brightness of simple colors like red, green, and blue. But I'm not sure how to change brightness of colors like purple, ...
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2 votes
2 answers
129 views

UNO's Internal EEPROM "read" returns incorrect values when it precedes "write"

I am an Arduino instructor and I was preparing some material on the utilization of the Arduino UNO's internal EEPROM when I encountered a problem. The problem is, I am trying to show the original ...
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1 vote
1 answer
115 views

Adding L293D motor shield to Breadboard

Anyone knows how to attach the l293D motor driver shield on a breadboard? I need to put the shield on top of a breadboard and then use an Atmega328P as the main way of controlling it. Than you :)
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1 vote
1 answer
49 views

can differential drive work together with ultrasonic sensor?

I've written a sketch to drive a differential drive system, specifically - to be able to drive strait. This does work. So I am trying to add the ability to stop when the path is blocked using US ...
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1 vote
1 answer
199 views

Is it possible to use a slide switch without a resistor?

I understand how pullup and pulldown resistors work with push buttons and I also understand that an analogous idea can be applied to slide switches. Furthermore, I know that some versions of Arduino ...
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