Community Digest

Top new questions this week:

How to Measure many voltages (Uno) - Analog extenders a good option?

I am trying to make a battery capacity tester (3.7v li-ion 18650 battery) using arduino uno. If possible i'd like to test 20 or more batteries at the same time. I need to measure the voltage of each ...

arduino-uno battery voltage analog  
asked by Maarten 1 vote
answered by david 0 votes

number generator show wrong segments on 7 segment display

I created a program to show a random number on a 7 segment display. It shows a random number in the serial monitor but always shows the same segments 'a c d and g'. anyone know hopw to fix this ...

arduino-uno 7-segment  
asked by Bavo 1 vote
answered by Michel Keijzers 0 votes

cant figure out how to fix this compile error

evrything worked for a bit and changed to much to get it working again. dont really understand the error. [![C:\Users\bavob\AppData\Local\Temp\ccyfrkaL.ltrans0.ltrans.o: In function `loop': ...

arduino-uno programming linker  
asked by Bavo 1 vote
answered by Michel Keijzers 2 votes

I can't receive string that I have sent through nrf correctly

I'm using arduino uno and nrf24l01. to monitor sensor data. But this is the message that master receives: βΈ® this is my slave code. void monitoring() { delay(10); radio.stopListening(); ...

arduino-uno arduino-ide string nrf24l01+ pointer  
asked by alireza 1 vote
answered by Michel Keijzers 1 vote

Issue connecting heartbeat & temperature sensor on arduino uno but working individually

So the code is working individually for temperature sensor and for heartbeat sensor but when i combine it together it shows wrong values for the temperature sensor #include <LiquidCrystal.h> ...

arduino-uno serial sensors pins temperature-sensor  
asked by Aref Ben Lazrek 1 vote
answered by Abel 1 vote

Measuring 12 V via voltage divider: choosing the right resistors

I want to measure a 9 V battery via one of the analog input ports of my Arduino Nano. From all the schemes of this great answer, I choose the simplest one, the voltage divider. Assuming the maximum ...

analogread voltage-divider  
asked by madhead 1 vote
answered by Edgar Bonet 2 votes

Greatest hits from previous weeks:

How do I convert a float into char*?

Asked this question on Electrical Engineering Stack Exchange and was directed here: Pretty self explanatory; how would I go about converting a float into a char*? I have code in which the float ...

arduino-uno c++ c float  
asked by higgsboson 9 votes
answered by John Burger 13 votes

Convert int to char[]

I'm looking to convert an int value to a char array. currently I've found the following will return [number] int num = [number] str = String(num); str.toCharArray(cstr,16); Serial.println(cstr); ...

arduino-mega string c-string  
asked by ATE-ENGE 3 votes
answered by Majenko 5 votes

How to toggle LED on button press?

I want to have a LED turn on when I push a button and go off when I push the button a second time. This code doesn't work: const int buttonPin = 4; const int motorPin = 10; const int ledPin = ...

asked by Coderboy 2 votes
answered by Peter Bloomfield 6 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 14 votes
answered by Ignacio Vazquez-Abrams 9 votes

Connecting ESP8266 with Arduino Uno - WiFi shield not present

I have an Arduino Uno and ESP8266. I want to connect and control an LED from a web server. I made a connection referring to this: I uploaded the WifiWebServer code to the Arduino, and applied my ...

arduino-uno esp8266  
asked by ABI 3 votes

How can I use stepper for specific degree?

I use Arduino and I'm beginner. I use the code below, but I don't understand what stepper.step(num) and STEPS in Stepper stepper(STEPS, 2,3,4,5) are, and I want to use stepper for specific degree and ...

asked by ReD 3 votes
answered by dhimaspw 4 votes

How can I handle the millis() rollover?

I need to read a sensor every five minutes, but since my sketch also has other tasks to do, I cannot just delay() between the readings. There is the Blink without delay tutorial suggesting I code ...

programming time millis  
asked by Edgar Bonet 73 votes
answered by Edgar Bonet 95 votes
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