Community Digest

Top new questions this week:

Can I use an accelerometer to measure the velocity of a car in a curve?

I am making an application that is used to measure the velocity, it has an accelerometer that measures the component acceleration in the XYZ-axis. When the car is moving just straight the measurement ...

accelerometer gyroscope  
asked by Gustavo Da Silva Ghedim 2 votes
answered by Gustavo Da Silva Ghedim 0 votes

Endurance of Arduino UNO during 24/7 operations and mild power fluctuations

I am designing an automation system for my research project and planning on using Arduino Uno to do the same. The program is to execute simple instructions based on few input parameters and does not ...

arduino-uno home-automation temperature  
asked by Atul DCT 2 votes
answered by chrisl 3 votes

When it comes to UART to RS485 communication, what is the difference between the 'MAX485' and the 'HW-0519' module?

I recently found this model with the ID 'HW-0519' on it. It can be found online (HW-0519 in Aliexpress) and is sold for the purpose of converting UART to RS485 communication using Arduino devices. The ...

serial sensors uart rs485 modbus  
asked by C Vith 2 votes

Serial plotter looks different and doesnt print graph

When I open my serial plotter to get the graph for my HC-SR04 sensor it doesn't show anything. My plotter looks different too. I have attached images below as well. Only those numbers on the top-most ...

asked by unibeam 2 votes
answered by Edgar Bonet 7 votes

Why SSD1306 OLED display get scrambled text when printing messages from separate tasks in RTOS? (revised)

ESP32 with RTOS, test app with 2 independent tasks. Each prints a message to OLED display. Why text gets frequently scrambled? Mutex have been used to share display resource. #define DEBUG_ESP ...

esp32 oled  
asked by Paulo Borges 2 votes
answered by sa_leinad 1 vote

Arduino NRF24LO1

I have a problem with transmiter (Arduino uno) and receiver (Arduino nao). When I am trsmiting that I receive that: An this is my code for receiver #include <SPI.h> #include <nRF24L01.h> #...

arduino-uno arduino-nano nrf24l01+  
asked by jaqb 2 votes

Read an integer using then read a string using Serial.readStringUntil(End-Char)

I have a sketch as follows: void loop() char End_Char = /n; if (Serial.available()) { aInt =; } switch (aInt) { case 1: // does a task that is ...

serial serial-data  
asked by Rob 1 vote

Greatest hits from previous weeks:

What are the 5V and VIN pins for?

I believe I can supply the Arduino with power in three different ways: Use USB. The design trusts the 5V to be regulated, and does not regulate it in any way. Use a regulated power source, trusted ...

asked by Mads Skjern 52 votes
answered by BrettAM 31 votes

What can I do if I run out of Flash memory or SRAM?

According to the Arduino documentation, the ATmega328 has 32KB of Flash memory for the bootloader + uploaded sketch, and only 2KB SRAM for runtime data. The ATmega2560 has quite a bit more, totalling ...

flash sketch-size  
asked by Peter Bloomfield 30 votes
answered by Peter Bloomfield 31 votes

Can I program for Arduino without having a real board?

I would like to start the development of some basic Arduino projects but I don't own an Arduino board yet. Is there a way I can write my code and emulate/test it using a desktop computer so after my ...

emulation testing  
asked by totymedli 225 votes
answered by Anindo Ghosh 134 votes

Turning all LEDs on (FAST.LED)

In Fast.Led lib for arduino there is a code to turn off all leds FastLED.clear (); Is there also a shortcut to turn all LEDs ON, and with a specific color

arduino-nano adafruit  
asked by Niles 8 votes
answered by Rob Hilken 9 votes

How can I get the source files for Arduino libraries?

I've been looking for a while inside Arduino's files to find the core library. However, I haven't found them yet. Where on my hard drive can I obtain the core library files (.cpp and .h) necessary for ...

library core-libraries  
asked by Anonymous Penguin 15 votes
answered by Ignacio Vazquez-Abrams 10 votes

What is the work of pulseIn?

I have code for an ultrasonic sensor which I found from a site. Here is the code: #define trigPin 12 #define echoPin 13 void setup() { Serial.begin (9600); pinMode(trigPin, OUTPUT); pinMode(...

arduino-uno sensors pulsein  
asked by shajib0o 9 votes
answered by sachleen 8 votes

How do you use SPI on an Arduino?

With reference to the Arduino Uno, Mega2560, Leonardo and similar boards: How does SPI work? How fast is SPI? How do I connect between a master and a slave? How do I make an SPI slave? Please note: ...

arduino-uno arduino-mega c++ arduino-leonardo spi  
asked by Nick Gammon 59 votes
answered by Nick Gammon 103 votes

Can you answer these questions?

How do you count objects (using ultrasonic sensor HCSR04) as 1, after they leave the trigger/echo path?

I found a simple code online that meets my goal to almost 100%, however when I place my hand in front of it, the number continues to count. I am trying to only count "1" when the solid ...

arduino-uno hc-sr04  
asked by Chris 1 vote

Initial setup print getting cut off from printing

I am writing a program in Python (using PySerial) that needs to read data from the Arduino quickly. For this reason I have set the serial timeout to 0.01 seconds. (Baud rate is 115k) If I don't set ...

serial python  
asked by ngpop 1 vote

Generating Externally Triggered Complimentary PWM with Arduino Due

I need a 2KHz complimentary PWM waves with adjustable duty and phase that is triggered by an external 4KHz source. After reading the datasheet I think there might be 2 way to do this: Use a TC unit ...

interrupt pwm arduino-due timers  
asked by 7E10FC9A 1 vote
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