Arduino and Nextion display with decimal numbers

Question

I have an Arduino MEGA with one of these Nextion displays. I created a nice display and my aim is to show analog inputs. However I have noticed that this display cannot show decimals (using the number "widget"). So I am using "text" widget to do that, unfortunately it doesn't work, anybody knows why?

#include "Nextion.h"
#define RES 1023
#define AREF 5
int voltage_pin=A0;
int raw_voltage;
double voltage;
String voltage2;

void setup() {
  Serial.begin(9600);
}

void loop() {
  raw_voltage=analogRead(voltage_pin);
  voltage=raw_voltage*AREF/RES;
  Serial.print("n3.val=");
  Serial.print(raw_voltage);
  Serial.write(0xff);
  Serial.write(0xff);
  Serial.write(0xff);
  String voltage2=String(voltage);
  Serial.print("t10.txt=");
  Serial.print(voltage2);
  Serial.write(0xff);
  Serial.write(0xff);
  Serial.write(0xff);
  delay(100);
}

Thanks in advance! :)

You probably should explain what you mean by "it doesn't work." — intrepidhero

walla walla · Accepted Answer · 2017-03-19T20:25:16

this could help:

value1 = analogRead(A1);

  vout1 = (value1 * AREF) / 1023.0; 

  vin1 = vout1 / (R2 / (R1 + R2));

  memset(buffer, 0, sizeof(buffer));

  dtostrf(vin1,5, 2, buffer);

  t4.setText(buffer);

  vin1 = map(vin1, 8, 15, 0, 100);

  send_ProgressBar("j2", vin1);

Arduino and Nextion display with decimal numbers

3 Answers