Questions tagged [constants]
Constants in programming are definitions whose value is fixed throughout a program's execution. Literals in most languages are constants, for example. In referentially transparent programming styles, all definitions are constant.
21 questions
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Code explanation when pH sensor is connected to Arduino
I have to measure the pH value for some experiment. I have checked various codes and all include the average of pH values.
#define SensorPin 0 // the pH meter Analog output is connected with ...
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How to know the data type of constant in arduino IDE?
For example constant of MSBFIRST, It used to as input in SPI.setBitOrder(MSBFIRST). But sadly i don't know the type data of MSBFIRST. This is applied to like SPI_MODE0 and other.
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Can data be stored in program storage space instead of dynamic memory?
I'm declaring an array at top level like so:
constexpr byte a[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, }; // whatever data
I'm referencing the array in such a way that it's not optimized away. When ...
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Increase or decrease const byte value inside the code with a push button
I'm kind of new in the Arduino world. I decided to make a self learning project with an Arduino where it controls a conveyor that simply moves from right to left and back again. There is a start and ...
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How to Set Sensor Data Parameters?
Good day! How to set sensor Data parameters?
Like the data only set for example it starts with minimum value of 3 and ends with maximum value of 6 and it will turn on led 1 and if minimum value of 1 ...
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Creating an array with the length coming from a library
When creating an array like in the sketch
#include <Lib.h>
int myArray[Lib::len];
void setup() {}
void loop() {}
the variable len must be an integer constant that is known at compile time. ...
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#define above static const int?
I see a lot of people, but also libraries, defining constants (like pin numbers, length of items etc) as #define:
#define LENGTH 5
While it is recommended to use in this case static const int:
...
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Optimizing for speed using const, static, constexpr etc in a function
In an ISR I want to keep things quick. At the same time I want to limit variable scope. Storage space is not a factor.
I have this line:
const char trigs[] = "aAbBcCdDeEfFgGhHiIjJ";
When this is ...
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Syntax of binary Constants
I was trying to compile some Arduino code on the PC for testing when I noticed some strange syntax for numerical binary constants.
Convetion seems to be to declare them like so:
static const ...
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Initialize and read from a PROGMEM array of pointers to PROGMEM arrays
I'm working on a project for the arduino uno for which I need multiple constant arrays of bytes. Such an array is initialized like so:
const byte charR[] PROGMEM = {
B01111111,//top half
...
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String & Char concatenations
A newbie in Arduino- and I'm trying to concatenate string and chars ( well in python it is quite different ).
I'm trying to post a MQTT message- constructed following format to the client.publish(...
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How to determine the source of constants in libraries?
Preamble:
I am trying to figure out how to program and use the timers in the Feather M0 using the Arduino IDE. I have seen a number of examples published, but I'm not one to just blindly copy some ...
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Best practice to declare a 'static' text and save memory
I'm working on a project where I need to create a JSON to send back state of an object. I created the code to achieve it and all works fine, but I used this to declare the JSON fields:
static const ...
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Why I'm getting this error: invalid conversion from 'const char*' to 'char' [-fpermissive]?
Why I'm getting this error?
invalid conversion from 'const char*' to 'char' [-fpermissive]
Here is my simple sketch:
const char data = "should";
//I have also tried:
//const char* data = "should";
...
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Constants within array of structs causes strange compiler errors?
In my sketch I have the following:
#define HU_ADDR 0x190;
#define ALL_AUDIO_ADDR 0x1FF;
#define MY_ADDR 0x360;
#define UNKNOWN_ADDR 0xFFF;
typedef ...
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