Error unknown typ name 'DS18B20'

mrjj

@AlexKrammer
Hi
But do you have such sensor ?
and hook it up to the board like they do here ?
https://www.circuitbasics.com/raspberry-pi-ds18b20-temperature-sensor-tutorial/

AlexKrammer

@mrjj yea for sure. but i want to use qt with c++. do create this application

mrjj

@AlexKrammer
I think you need a c++ lib then like
https://github.com/TeraHz/DS18B20
to interface with the hardware.

AlexKrammer

@mrjj to interface with the hardware ill use wiringpi. thats work good. i can turn on und off leds and i can read pins.
how does this lib work?

AlexKrammer

@mrjj ou i just saw. it looks like that one right?
"are you using the DS18B20::DS18B20(const char* address) version"

mrjj

@AlexKrammer
Heh yes but on this is says it should work with PI
and it has more includes.
So maybe this will actually work once we find out what that address should be :)

AlexKrammer

@mrjj
Now i tried to evaluate the temperatur with the c++ library.
The code looks good. There is no error, but if i run the projekt. its going to do this step

char w1_address [ 16 ];
DS18B20 w1Device1 (w1_address);
tempNow = w1Device1. getTemp ();

its going to crash. So i think there is a mistake in the adress.
i put in the raspberry pin.

mrjj

@AlexKrammer
im not sure a pin is right there.
Try read some the many tuts and see what they use for adress.

AlexKrammer

@mrjj
Now it works.
i reached the slave-address each sensor, made a code like this

char w1_address[16];
const char* adr1  = "10-000803673bfb";
DS18B20 w1Device1 (adr1);
actualTemp1 = w1Device1.getTemp();

And it's working.
But unfortunately if i add a new sensor. i have to find out his address and add it to the code. its not only plug and play^^

But now a basic c++ problem.
I created a class:
checktemperature.h

#ifndef CHECKTEMPERATURE_H
#define CHECKTEMPERATURE_H

#include <settemperature.h>
#include <readtemperature.h>
#include <wiringPi.h>

class CheckTemperature
{
private:
    SetTemperature S;
    ReadTemperature R;
public:
    void CheckTemp();
    float TempEin;
    float TempAus;
};

#endif // CHECKTEMPERATURE_H

checktemperature.cpp

#include "checktemperature.h"

void CheckTemperature::CheckTemp()
{
    TempEin = S.getHystTemperature();
    TempAus = S.getHystTemperature();

    if (R.actualTemp1 <= TempEin) digitalWrite(31, LOW);
    else if (R.actualTemp1 >= TempAus) digitalWrite(31, HIGH);

    if (R.actualTemp2 <= TempEin) digitalWrite(26, LOW);
    else if (R.actualTemp2 >= TempAus) digitalWrite(26, HIGH);

    if (R.actualTemp3 <= TempEin) digitalWrite(27, LOW);
    else if (R.actualTemp3 >= TempAus) digitalWrite(27, HIGH);

    if (R.actualTemp4 <= TempEin) digitalWrite(28, LOW);
    else if (R.actualTemp4 >= TempAus) digitalWrite(28, HIGH);

    if (R.actualTemp5 <= TempEin) digitalWrite(29, LOW);
    else if (R.actualTemp5 >= TempAus) digitalWrite(29, HIGH);
}

i call that funktion every 500ms in loop.
But the values of R.actualTemp and S.getHystTemperature the value does not adjust, so they still at the moment when i start the program.
Do you know whats wrong, cause i call that funktion every 500ms and at the beginning "TempEin= ..." and S.getHystTemperature(); is already changing^

mrjj

@AlexKrammer
Hi
So it works fine the first time you run ?
Have you checked with debugger what happens when you read and set
R.actualTemp1 ?

Its hard to guess from this code.

AlexKrammer

@mrjj
yes it works. its still working. Thats a other problem.
So R.actualTemp is the temperature from the sensor.
if i show the R.actualTemp is changing his value.
So if i show S.getHystTemperature(); its changing the value too.

But if i show e.g. TempEin its not changing the Value its always the value as i run the program.

A other example. If i put R,actualTemp into a variable in this class and im going to show the variable. its dont change the value too. If i show R.actualTemp its changing.

Are you understanding my problem?

mrjj

@AlexKrammer
Hi
Your naming confuses me a bit. :)
So S.getHystTemperature(); changes but
TempEin = S.getHystTemperature(); dont ?

AlexKrammer

@mrjj
Ohhh im sry TempEin means TempOn, TempAus means TempOff:)
I like to show you my completely code but i dont know how:P

yes if i try to: qDebug() << S.getHystTemperature(); in mainwindow.cpp
the value is changing in relation when im moving the horizontal slider.
The same with R.actualTemp.
But if i try to: qDebug() << S.getHystTemperature(); in checktemperature.cpp
its taking the value of the veriable when i run the program. e.g. i declared in setTemperature.h "float HystTemperature;" So its got value 0;
So qDebug() just show 0.

In conclusion it can be said that in class CheckTemperature the variable and values do not adapt to the current values. They stuck on the values when the program start to run.

mrjj

@AlexKrammer
And you only have one instance of the CheckTemperature class?
since S.getHystTemperature(); in mainwindow.cpp Works
it should also in CheckTemperature so i wonder if you have 2 of them or something like that ?

AlexKrammer

@mrjj
no i only have one instance.
i only have one checktemp in class CheckTemperature, one gethysttemperature() in class SetTemperature, and one actualTemp in class ReadTemperature.
thats why im wondering too.
cause im calling checktemp() every 500ms in loop mainwindow.

Is there any possibility that i can't call object in a method of a single class. But there is no sense

mrjj

@AlexKrammer
That is very odd then.
The 500ms loop is a QTimer?

Sorry I cant guess what could be wrong. It sounds like the parts are working but
not in all use cases.

AlexKrammer

@mrjj yes for sure. other thing in the loop are working. e.g. if i call directly in the loop every 500ms "ui->temperature4lable->setText(QString::number(S.getHystTemperature()));"
the value changes every 500ms if i change the horizontal slider.

mrjj

Hi
Ok but that
S.getHystTemperature()
seems out side of the CheckTemperature class, correct ?

so you have
SetTemperature S;
ReadTemperature R;

in mainwindow too ? and those works but
inside the CheckTemperature they are not ?

AlexKrammer

@mrjj yes. right.
but i have:
SetTemperature S;
ReadTemperature R;

in CheckTemperature too

mrjj

@AlexKrammer
and that's the part that really bugs me as if those classes work alone in MainWindow, i cannot see a reason they should not work in that other class just the same ??

void CheckTemperature::CheckTemp()
could just have well been

void MainWindow::CheckTemp()

and the difference is really small.