Help Nextion display - temperature / humidity with photon

For france you’d need to set Time.zone(+2.0) (DST) or +1.0 for Central European Standard Time.

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Ah yes, thank you, I saw this line, but I didn’t know the number inside corresponded to hour hour, I wanted to add…

So, everything seems to be ok now, but there is something strange anyway. The temperature sensors worked fine at the beginning, and since a moment (but don’t know when) it begins to show some weird values (increase to 40 ºC to decrease to 25 ºC, which is the good temperature).
I thought it was a voltage problem due to the amount of thing plugged on the Photon, but I tested the voltage and it’s the same than without anything plugged.

I am also using some if loop to trigger delays when the temperature and the hour reach the values I set. And to do so, I am using comparison but sometimes, this comparison are inversed : less than equal more than, more than equal less than and about the delay, HIGH equal LOW and LOW equal HIGH.
I know it’s really strange, It’s the first time I have something like that, I checked the connections and everything is good.
I don’t understand why.

This is all the code I flashed in my Photon, I am pretty sure there is many thing that can be changed, but I am a novice :slight_smile:

I had to add another buffer and to use the first way I did to display the humidity on the screen because the code you gave me didn’t works. I had the temperature from one of my sensors instead of the humidity, I on’t know why because I checked every line, because I thought there was a conflict, but nothing :confused:

About the calcul of the temperature sensors to convert voltage into degrees, I also had to modify the values, otherwise, with 5.0 (there are plugged on the VIN) the values was like -5.8 ºC.

////// LIBRARIES ///////
#include <ITEADLIB_Nextion.h>
#include <Adafruit_DHT.h>



////// TEMPERATURE ///////
int chaudHaut = A0;
int chaudBas = A1;
int froid = A2;


////// HUMIDITY ///////
#define DHTPIN A3
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);


////// RELAYS ///////
int relayLed = D0;
int relayLampe = D1;
int relayTapis = D2;
int relay4 = D3;
int relay5 = D4;


////// LED ///////
int led = A4;
int brightness = 0;
int fadeAmount = 2;


////// DISPLAY ///////
USARTSerial& nexSerial = Serial1;

NexText t0 = NexText(0, 4, "t0"); // chaud haut
NexText t1 = NexText(0, 5, "t1"); // chaud bas
NexText t2 = NexText(0, 6, "t2"); // froid
NexText t3 = NexText(0, 7, "t3"); // humidity
NexText t8 = NexText(0, 12, "t8"); // hour
NexText t10 = NexText(0, 13, "t10"); // day
NexText t11 = NexText(0, 14, "t11"); // month
NexText t12 = NexText(0, 15, "t12"); // year

int hour = Time.hour();
int format = Time.hourFormat12();



void setup() {
    Time.zone(+2.0);
    
    
    pinMode(chaudHaut, INPUT);
    pinMode(chaudBas, INPUT);
    pinMode(froid, INPUT);
    
    
    ////// HUMIDITY ///////
    dht.begin();
    
    
    ////// RELAYS ///////
    pinMode(relayLed, OUTPUT);
    pinMode(relayLampe, OUTPUT);
    pinMode(relayTapis, OUTPUT);
    pinMode(led, OUTPUT);
    pinMode(relay4, OUTPUT);
    pinMode(relay5, OUTPUT);
    
    digitalWrite(relay4, HIGH);
    digitalWrite(relay5, HIGH);
    
    
    
    ////// DISPLAY ///////
    nexInit();
    
    
    
}




void loop() {
    /////////////////////////////////////////////////////////////// TEMPERATURE ///////////////////////////////////////////////////////////////
    ////////// Sonde chaud haut //////////
    int readingCH = analogRead(chaudHaut);  
    float voltageCH = readingCH * 0.8; //20
    voltageCH /= 1024.0;
    float tempCH = (voltageCH - 0.5) * 100;
    
  
    ////////// Sonde chaud bas //////////
    int readingCB = analogRead(chaudBas);  
    float voltageCB = readingCB * 0.8; //20.5
    voltageCB /= 1024.0;
    float tempCB = (voltageCB - 0.5) * 100;
  
  
    ////////// Sonde froid  //////////
    int readingF = analogRead(froid);  
    float voltageF = readingF * 5; //20.5
    voltageF /= 1024.0;
    float tempF = (voltageF - 2) * 100;
    
    
    
    /////////////////////////////////////////////////////////////// DISPLAY ///////////////////////////////////////////////////////////////
    char buffer [64];
    char buffer1 [64];
    int humi = dht.getHumidity();
    
    snprintf(buffer, sizeof(buffer), "%.1f", tempCH);
    t0.setText(buffer);
    
    snprintf(buffer, sizeof(buffer), "%.1f", tempCB);
    t1.setText(buffer);
    
    snprintf(buffer, sizeof(buffer), "%.1f", tempF);
    t2.setText(buffer);
    
    t3.setText(buffer1);
    memset(buffer1, 0, sizeof(buffer1));
    itoa(humi, buffer1, 10);


    
    snprintf(buffer, sizeof(buffer), "%s", (const char*)Time.format("%T"));
    t8.setText(buffer);
    
    snprintf(buffer, sizeof(buffer), "%s", (const char*)Time.format("%D"));
    t10.setText(buffer);
    


    
    /////////////////////////////////////////////////////////////// RELAYS ///////////////////////////////////////////////////////////////
    if(hour >= 10){
        digitalWrite(relayLed, LOW);
        analogWrite(led, brightness);
        
        if (brightness < 100) {
            brightness = brightness + fadeAmount;
        }
    }
    
    
    
    if(tempCB < 31){ //this part works fine now, but something it's inversed
        digitalWrite(relayTapis, LOW); //here LOW works like HIGH
    }else{
        digitalWrite(relayTapis, HIGH);  //here HIGH works like LOW
    }
    
    
    if(tempCH < 31){
        digitalWrite(relayLampe, LOW);
    }else{
        digitalWrite(relayLampe, HIGH);   
    }
    
    
    
    if(hour >= 22){
        digitalWrite(relayLed, HIGH);
        
        /*if(tempCH > 28){
            digitalWrite(relayLampe, LOW);
        }else{
            digitalWrite(relayLampe, HIGH);   
        }
        
        if(tempCB > 28){
            digitalWrite(relayTapis, LOW);
        }else{
            digitalWrite(relayTapis, HIGH);   
        }*/
    }
    
    
    
    delay(8000);
}

Your voltageXX /= 1024.0; should actually be voltageXX /= 4095.0; since the ADCs on the Particle devices have 12bit resolution unlike Arduino which use 10bit.
Also the factor 0.8 (and 5) would probably need adjusting for the 3.3V logic - be carefule not to feed any voltage higher than 3.3V into analog INPUT pins.

I don’t really like repeating myself but you still got that wrong - hence the code didn’t work, since this is not what I gave you but what you had wrong right from the beginning

    t3.setText(buffer1);
    memset(buffer1, 0, sizeof(buffer1));
    itoa(humi, buffer1, 10);

you can’t set the text before you put the value into the buffer!

If you get the order right, you will also get the correct values in the correct fields.

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It works better indeed, thank you, I thought it was the same ADCs.
But, I still have huge different values when the sensors refresh one time I have 28 and then 31 etc. there is nothing fix however the temperature is fixed I don’t know where is the problem. I’m using TMP36 sensors plugged on the 3V3 and this is the code modified with your advice:

    int readingCH = analogRead(chaudHaut);  
    float voltageCH = readingCH * 3.3; //20
    voltageCH /= 4095.0;
    float tempCH = (voltageCH - 0.5) * 100;

I’m sorry I wouldn’t offend you, It works fine for the temperature and I thank you a lot for your help, but not for the humidity, that’s why I reuse the first thing I found with another buffer.

Actually I thought I had understand but apparently not,

If I put the value on the buffer and then I set the text, like this (that’s what I understood)

memset(buffer1, 0, sizeof(buffer1));
t3.setText(buffer1);
itoa(humi, buffer1, 10);

It doesn’t work. But I really would use your method, but I tried everything again and again and nothing works, I still have the temperature of one of the sensors.

memset(buffer1, 0, sizeof(buffer1));
t3.setText(buffer1);
itoa(humi, buffer1, 10);

Still not

memset(buffer1, 0, sizeof(buffer1)); // this only CLEARS the buffer
itoa(humi, buffer1, 10); // this converts the numeric data into string and stores in buffer1
t3.setText(buffer1); // only after both of the above you can send it to the display

And this will still work

    snprintf(buffer, sizeof(buffer), "%d", humi);
    t3.setText(buffer);

The reason why my code provided above didn’t work for you must have been due to the fact that you are using an int (which needs a %d in snprintf()) while I used a double (which requires the provided %f).

You can’t just take the one line without considering the other - consistency is key here.

To get better readings of your TMP36 you may want to search the forum for TMP36 and TMP35 to find how to improve reading quality.

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Hi @ScruffR
sorry for my late reply. I could continue my project and I understand better the way of using Nextion display. I used your code for the humifity and its works fine now.
Thank you again for your help and your time.

I still have some difficulties to have stable values from the temperature sensors (even with a 0.1 cap) but I’ll continue to look for a solution. And after some complication I finally could automatically switch on and off the light plugged on a relay. At the beginning I was using an if but that doesn’t worked and then I found the TimeAlarm library that is pretty easy to use and it’s way better.

So thank you again for everything !

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