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Unanswered Questions

1,686 questions with no upvoted or accepted answers
0 votes
0 answers
36 views

How to wire a 9v power supply to an LED matrix and power Arduino Uno?

So I've been looking for some advice but I can never find a good answer. My current project requires me to externally power a btf lighting 22*22 matrix to an external power supply. I bought one from ...
1 vote
0 answers
28 views

arduino micro A000053 disappear at device manger

I have two Arduino micro atmega32u4 boards (A000053) and I'm trying to detect them with at Device manger but I'm stuck, I tried to solve it with the guide below but not succeed because the device ...
-1 votes
1 answer
52 views

MFRC522 RFID RC522 Only Works Sometimes – Unreliable Detection Issue

Problem Overview I’m using an MFRC522 RFID module with an Arduino Uno, and it only detects RFID tags sometimes. The behavior is inconsistent—sometimes it reads the card instantly, and other times, it ...
0 votes
0 answers
52 views

How to Connect/configure HC05 (Bluetooth module) to a shield?

I am a newbie to Bluetooth communication in Arduino. I have 2 Arduino boards (one runs my main sw, second act as slave to operate a remote command coming from the main board) that i want to establish ...
0 votes
0 answers
53 views

ESP8266 Not Booting Properly on First Power On – Works After Restart

I'm working on an ESP8266-based water level monitoring system using an ultrasonic sensor and an I2C LCD. The problem I'm facing is that sometimes the ESP8266 does not boot properly when powered on for ...
1 vote
1 answer
50 views

Push button isn't pushed but keeps printing or inputting 1/HIGH

I have this Arduino code that will print 1 in the serial monitor and even prints two 1's. I haven't even pushed or clicked the push button, yet it already is already set to HIGH and even activates to ...
0 votes
1 answer
56 views

Alternate LED Blinking Using PushButton

I have an task for my class where we have to make 2 LEDS blink alternatively using a pushbutton. I've figured out how to do the blinking and alternating but from time to time one of the led would go ...
-1 votes
1 answer
74 views

FastLED with WS2812B 241228

Hello Arduino Stack Exchange forum, Learning how to use the FastLED to control a string of 150 WS2812B LEDs Code copied herewith below compiles and operates as expected. Trying to figure out how to ...
-1 votes
1 answer
55 views

Using arduino to power another usb device

Can I configure an Arduino Uno as a power source to recharge a USB device while being powered by another external power device? I asked ChatGPT for input and it gave me this code: #include <USBHost....
-1 votes
2 answers
87 views

50 Hz powerline noise using Arduino and mikroe ECG 2 (ADS1194)

I am trying to take ECG measurements using the Mikroe ECG 2 (ADS1194), connected to an Arduino Uno via an Arduino Uno Click shield. I am able to measure the ECG, and can read the heartbeats somehow in ...
-1 votes
2 answers
59 views

Reading the state of a pin at 35V using arduino at 5V

I have a gate controlled by a motorline MC2 motherboard. I want to add a distance sensor controlled by arduino so that I can give it the opening command when leaving the yard. From what I have seen, ...
-1 votes
1 answer
54 views

Running full voltage through Transistors

Hello I am trying to create a fan controller using Arduino. The (Placeholder LED's) fans run at 12V 0.23A DC so I have an external power supply for them. I plan to control the flow of this with NPN ...
1 vote
2 answers
82 views

Arduino keeps restarting with L9110 and DC motor

I am trying to control a DC motor using the L9110 motor driver and Arduino MEGA 2560. Here's the code. #include <Arduino.h> const int rightA = A3; const int rightB = A2; void setup() { ...
0 votes
1 answer
90 views

How to run G code with SoftwareSerial?

I'm trying to build my own CNC machine. Since I need to control a large number of motors at the same time, I want to control it via an Arduino master and several slaves with CNC shields. Now I'm ...
1 vote
1 answer
187 views

LCD display connection without a resistor

Can run a LCD without a potentiometer or a resistor? I don't have any. Here it said to connect both:

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