hello I've added some code to my project to convert an intigar to a string then a char, however when its converted to a string only the first digit of the int gets displayed (e.g. int = 3.14 and the string value = 3)
below is the section of code that does the conversion.
int a=v2; //declaring integer
char b[2]; //declaring character array
String str; //declaring string
char input[30];
str=String(a); //converting integer into a string
str.toCharArray(input, 30);
the v2 is the int that is being converted into char input
str=String(a); //converting integer into a string
str.toCharArray(input, 30);
To convert a numeric variable to a character array, you don't need to use Strings (capital S). You can go directly to a character array aka (small s) string using sprintf.
What do you want to do with the character array once it has the numeric value converted into it?
#include "ST7565.h"
const int numReadings = 10;
int readings[numReadings]; // the readings from the analog input
int index = 0; // the index of the current reading
int total = 0; // the running total
int average = 0; // the average
int inputPin = A0;
float vPow = 4.9;
float r1 = 18000;
float r2 = 4700;
int psu = 3;
// the LCD backlight is connected up to a pin so you can turn it on & off
#define BACKLIGHT_LED 10
// pin 9 - Serial data out (SID)
// pin 8 - Serial clock out (SCLK)
// pin 7 - Data/Command select (RS or A0)
// pin 6 - LCD reset (RST)
// pin 5 - LCD chip select (CS)
ST7565 glcd(9, 8, 7, 6, 5);
#define LOGO16_GLCD_HEIGHT 16
#define LOGO16_GLCD_WIDTH 16
void setup() {
Serial.begin(9600);
// turn on backlight
pinMode(BACKLIGHT_LED, OUTPUT);
digitalWrite(BACKLIGHT_LED, HIGH);
// initialize and set the contrast to 0x18
glcd.begin(0x18);
glcd.clear();
for (int thisReading = 0; thisReading < numReadings; thisReading++)
readings[thisReading] = 0;
// Send ANSI terminal codes
Serial.print("\x1B");
Serial.print("[2J");
Serial.print("\x1B");
Serial.println("[H");
// End ANSI terminal codes
Serial.println("--------------------");
Serial.println("DC VOLTMETER");
Serial.print("Maximum Voltage: ");
Serial.print((int)(vPow / (r2 / (r1 + r2))));
Serial.println("V");
Serial.println("--------------------");
Serial.println("");
delay(2000);
}
void loop() {
// subtract the last reading:
total= total - readings[index];
// read from the sensor:
readings[index] = analogRead(inputPin);
// add the reading to the total:
total= total + readings[index];
// advance to the next position in the array:
index = index + 1;
// if we're at the end of the array...
if (index >= numReadings)
// ...wrap around to the beginning:
index = 0;
// calculate the average:
average = total / numReadings;
analogWrite(psu, 56);
float v = (average * vPow) / 1024.0;
float v2 = v / (r2 / (r1 + r2));
int a=v2; //declaring integer
char b[2]; //declaring character array
String str; //declaring string
char input[30];
str=String(a); //converting integer into a string
str.toCharArray(input, 30); //passing the value of the string to the character array
glcd.clear();
glcd.drawstring(0, 5, input);
glcd.display();
Serial.println(b);
delay(1000);
}
the idea simpily is that it reads A0 smooths the reading, by creating an average. then a voltage decider calculation calculates a voltage (witch is v2 and usually = 3.14) then that gets converted to a char and displayed on an lcd once per second
thanks again for your time
Edit - the serialprint(b) was set for testing and will usually be serialprint(input)
Thanks I recompiled and ran the code however on the LCD there's just a '?' (See attached picture)
I've tried using dtostrf() however that wouldn't compile at all
