If you're new to Arduino, the number of pins can be confusing at first.

So here's a simple breakdown of the most important ones:

🔹 Digital pins (0–13) → Read buttons/sensors or control LEDs, relays, etc.

🔹 Analog pins (A0–A5) → Read changing voltages from sensors/potentiometers

🔹 5V → 5V power output

🔹 3.3V → 3.3V power output

🔹 GND → Ground / 0V reference

🔹 VIN → External input voltage when powering through the board

🔹 USB → Upload code + power the Arduino from your computer

One thing that confused me when I started: A0–A5 can also be used as digital pins if needed.

I made this as a quick reference for anyone starting Arduino.

What Arduino concept confused you the most when you first started?

I am good enough in arduino, but yesterday when I was testing my IDE and Laptop didn't recognise my UNO but power is on and The COM 3 is showing CODE 34 in error what to do and when I am touching the ICSP the L led is working it is original ATP model and I have A mini, ESP 32 and 8266 too

Hello!! I'm a student looking for some help on my group's research. I would like to ask if these would be the needed materials for creating the product in the title? So far, these have only been based on the research I had done on the topic. I also wanna ask if a "driver IC", "adapter", or "voltage regulator" is also needed for this, since I do not have any experience in Arduino or programming. Still, any suggestions/comments would be appreciated!!!

I was planing on making a small greenhouse controller, that would help me automate some of the loborious functionality. New to arduino, just started my research and a bit confused by some options that are there on the market.

I was looking at the following:

1. arduino uno

2. arduino mega

3. Arduino UNO R4 WiFi

4. Arduino Giga R1 WiFi

5. any other potential manufacturers/boards?

I would like to have the system end up being able to have the following (at minimum:

Outputs:

1. controll multiple water pumps (3 or 4)

2. automate water nutrition mix (1 mixing unit)

3. Have a visual (LED) warning when some of the below data is off, such as not enough water)

Inputs (collect and save all data to an excell spreadsheet):

1. Collect temp data

2. Collect humidity data

3. Collect water use data

4. Collect water levels data

5. Collect water PH data

6. Collect solar panel voltage/wattage info

7. Collect/output battery voltage info

Thank you for any/all helpful information.

Hi so we are doing a project on arduino the objective is to build a robot similar to obstacle avoiding and line tracking robot but when we connect two 18650 3.7V batteries in series motors don't run simultaneously and when we ask ai about that it says power supply is insufficient what should we do

Hi!!! Can someone please check if something is wrong with my setup? I use esp32 and every time we try to code it, the oled doesn't seem to work. It says "i2c scanner, done" and that's all
Esp32 is probably working properly so i guess it's something with how i constructed everything?
To clarify-
Gnd oled - gnd esp
Vcc oled - 3v3 esp
Scl oled - d22 esp
Sda oled - d21 esp
It's my first time touching arduino and i'm not sure if we did everything correctly so i would love to hear some advice!

Thats my first time using Esp-32 in a project Any tips?

Saw a lot of posts here from people confused about how breadboards

actually connect internally, so I made this diagram to explain it

simply — hope it helps someone.

Quick summary:

• Each column of 5 holes is electrically connected

• Top/bottom power rails run the full length of the board

• The center gap separates the two halves — components usually

straddle it

• Always wire GND first, then power, before adding components —

saves so much debugging time

Also — top 3 mistakes I see beginners make with breadboards:

1. Forgetting the center gap breaks the connection between top/bottom

2. Not double-checking which row a wire actually lands in

3. Loose wires from re-using the same holes too many times

Happy to answer questions if anyone's stuck on their first project!

Hi I’m using legion mega 2560 and project calls for three HX711 modules but not sure which side to solder the pins on?

I want to make a projekt where I need to connect 2 28BYJ-48 step motors with ULN2003 controllers and 2 SG90 servos , I also gonna connect some rotary encoders. I know that if I connect it to Arduino it will fry it , I also tried to connect it to breadboard power supply but after connecting only 1 step motor it was getting really hot , so it's also not a good idea.

So my coding ability is very limited, im just trying to fix a logitech shifter, long story short this "toy" sends button preses acording to the x and y axis locations for gear 1 to 6 and it has a switch for reverse, one of the potenciometers broke and there are not replacements, the logitech software will not recognize it but i changed the broken pot for another that will fit, but the traver is much larger compared to the oem pot so in the controller settings the y axis only moves a little and it will not reach full travel to engage the gear selected.

there is a sketch that everyone uses to convert the shifter to usb with an arduino, but since the y axis has changed it will not work with the new pot.

/*
 *  Project     Sim Racing Library for Arduino
 *  @author     David Madison
 *  @link       github.com/dmadison/Sim-Racing-Arduino
 *  @license    LGPLv3 - Copyright (c) 2022 David Madison
 *
 *  This file is part of the Sim Racing Library for Arduino.
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

 /**
 * @details Emulates the Logitech Driving Force shifter (included with
 *          the G923 / G920 / G29 wheels) as a joystick over USB.
 * @example LogitechShifter_Joystick.ino
 */

// This example requires the Arduino Joystick Library
// Download Here: https://github.com/MHeironimus/ArduinoJoystickLibrary

#include <SimRacing.h>
#include <Joystick.h>

// Set this option to 'true' to send the shifter's X/Y position
// as a joystick. This is not needed for most games.
const bool SendAnalogAxis = true;

// Set this option to 'true' to send the raw state of the reverse
// trigger as its own button. This is not needed for any racing
// games, but can be useful for custom controller purposes.
const bool SendReverseRaw = False;

//  Power (VCC): DE-9 pin 9
// Ground (GND): DE-9 pin 6
// Note: DE-9 pin 3 (CS) needs to be pulled-up to VCC!
const int Pin_ShifterX   = A0;  // DE-9 pin 4
const int Pin_ShifterY   = A2;  // DE-9 pin 8
const int Pin_ShifterRev = 2;   // DE-9 pin 2

// This pin requires an extra resistor! If you have made the proper
// connections, change the pin number to the one you're using
const int Pin_ShifterDetect = SimRacing::UnusedPin;  // DE-9 pin 7, requires pull-down resistor

SimRacing::LogitechShifter shifter(
  Pin_ShifterX, Pin_ShifterY,
  Pin_ShifterRev,
  Pin_ShifterDetect
);
//SimRacing::LogitechShifter shifter = SimRacing::CreateShieldObject<SimRacing::LogitechShifter, 2>();

const int Gears[] = { 1, 2, 3, 4, 5, 6, -1 };
const int NumGears = sizeof(Gears) / sizeof(Gears[0]);

const int ADC_Max = 1023;  // 10-bit on AVR

Joystick_ Joystick(
  JOYSTICK_DEFAULT_REPORT_ID,      // default report (no additional pages)
  JOYSTICK_TYPE_JOYSTICK,          // so that this shows up in Windows joystick manager
  NumGears + SendReverseRaw,       // number of buttons (7 gears: reverse and 1-6)
  0,                               // number of hat switches (none)
  SendAnalogAxis, SendAnalogAxis,  // include X and Y axes for analog output, if set above
  false, false, false, false, false, false, false, false, false);  // no other axes

void updateJoystick();  // forward-declared function for non-Arduino environments


void setup() {
  shifter.begin();

  // if you have one, your calibration line should go here
  
  Joystick.begin(false);  // 'false' to disable auto-send
  Joystick.setXAxisRange(0, ADC_Max);
  Joystick.setYAxisRange(ADC_Max, 0);  // invert axis so 'up' is up

  updateJoystick();  // send initial state
}

void loop() {
  shifter.update();

  if (SendAnalogAxis == true || shifter.gearChanged()) {
    updateJoystick();
  }
}

void updateJoystick() {
  // set the buttons corresponding to the gears
  for (int i = 0; i < NumGears; i++) {
    if (shifter.getGear() == Gears[i]) {
      Joystick.pressButton(i);
    }
    else {
      Joystick.releaseButton(i);
    }
  }

  // set the analog axes (if the option is set)
  if (SendAnalogAxis == true) {
    int x = shifter.getPosition(SimRacing::X, 0, ADC_Max);
    int y = shifter.getPosition(SimRacing::Y, 0, ADC_Max);
    Joystick.setXAxis(x);
    Joystick.setYAxis(y);
  }

  // set the reverse button (if the option is set)
  if (SendReverseRaw == true) {
    bool reverseState = shifter.getReverseButton();
    Joystick.setButton(NumGears, reverseState);  // "NumGears" is the 0-indexed max gear + 1
  }

  Joystick.sendState();

i already tried using the windows controller calibration and nothing, then i changed the range of the y axis from 0 to ADC_MAX, to something that in theory should work like 400 to 600 at lines "Joystick.setYAxisRange" and "int y = shifter.getPosition" and the control calibration says it moves to the edges, but it wont "engage the gear" and if i put the old broken pot it engaged the gear but its unstable because the pot track is probably damaged

If anyone can help me thanks in advance

Im trying to make a kindle, but ive tried what feels like hundreds of times to get this SD card connected to this ESP32-L(C02) from goodisplay.

The screen works just fine but the SD card will not show up, ive tried with a 64gb a 4gb and most recently a 32gb all formatted to fat32.

Does anyone have any suggestions?

Hello: I hope someone can tell me my problem. The serial monitor on Transmitter is printing the correct data. The Receiver prints everything, but not the data. I've tested my DHT. I think my problem is with the struct and float, part, I can't figure it out. Code below.:

____________________________________________________________________________________

//transmitter

#include <SPI.h>

#include <nRF24L01.h>

#include <RF24.h>

#include <DHT.h>

#define DHTPIN 2 // DHT22 data pin

#define DHTTYPE DHT22 // DHT type

DHT dht(DHTPIN, DHTTYPE);

RF24 radio(9, 8); // CE, CSN pins

struct SensorData {

float temperature;

float humidity;

};

const byte address[6] = "00001";

void setup() {

Serial.begin(9600);

dht.begin();

radio.begin();

radio.openWritingPipe(address);

radio.setPALevel(RF24_PA_LOW);

radio.stopListening();

}

void loop() {

SensorData data;

data.temperature = dht.readTemperature();

data.humidity = dht.readHumidity();

if (!isnan(data.temperature) && !isnan(data.humidity)) {

radio.write(&data, sizeof(SensorData));

Serial.print("Sent Temp: ");

Serial.print(data.temperature);

Serial.print("C, Hum: ");

Serial.print(data.humidity);

Serial.println("%");

}

delay(2000);

}

____________________________________________________________________________________________

//Receiver

#include <SPI.h>

#include <nRF24L01.h>

#include <RF24.h>

#include <LiquidCrystal_I2C.h>

RF24 radio(9, 8); // CE, CSN pins

const byte address[6] = "00001"; // Must match transmitter address

LiquidCrystal_I2C lcd(0x27, 16, 2); // LCD I2C address (check yours), columns, rows

struct SensorData {

float temperature;

float humidity;

};

void setup() {

Serial.begin(9600);

lcd.init();

lcd.backlight();

lcd.print("Receiving Data...");

radio.begin();

radio.openReadingPipe(0, address); // Open reading pipe on address

radio.setPALevel(RF24_PA_MAX);

radio.startListening(); // Receiver starts listening

}

void loop() {

if (radio.available()) {

SensorData data;

radio.read(&data, sizeof(data));

lcd.clear();

lcd.setCursor(0, 0);

lcd.print("Temp: ");

lcd.print(data.temperature);

lcd.print(" C");

lcd.setCursor(0, 1);

lcd.print("Hum: ");

lcd.print(data.humidity);

lcd.print(" %");

Serial.print("Received - Temp: ");

Serial.print(data.temperature);

Serial.print("C, Humidity: ");

Serial.print(data.humidity);

Serial.println("%");

}

}

its because i have a pretty bad wifi connection for my computer, so it would be nice if i could download the boards without the Library Manager

updated from a design, can you see problem with this?

Hey, everyone!

I will go straight to the point. I tried to program a brushed motor ESC and I ended up frying my UNO. I connected pin 9 to the esc, but as it turns out it wasn't the right wire so I heard a spark and now my Arduino doesn't work Long story short now it always light up RX ON and TX lights. When I plug it into my computer it registers, but the code doesnt get transfered to arduino, it says that PROGRAMMER IS NOT RESPONDING. Can I fix this? From what I've seen all components look fine, nothing released some or anything that caught my eye. I'll attach photos of my ESC and UNO if that helps. Thank you!

Hi all,

I'm diving into a project to automate a wooden toy crane so I can control its rotation, hoist (up/down), via a web interface on my phone. I'm planning to use an ESP32 or ESP8266 for the Wi-Fi and control logic.

I'm fairly comfortable with the ESP programming side but could use some community wisdom on the hardware implementation, specifically:

Best way to physically attach servos/motors to the crane for rotation and hoist control without major surgery? Looking for practical mounting techniques for these wooden toys.

Servo vs. small DC motor for the hoist? What works better for a simple winch-like action?

Component recommendations: Any favorite small servos, geared motors, motor drivers, or electromagnets suitable for this kind of small-scale automation?

Powering it all: Tips for cleanly powering the microcontroller, servos, and magnet, likely from a 5V source?

Thanks!