# Particle.publish Particle.subscribe

**URL:** <https://community.particle.io/t/particle-publish-particle-subscribe/57949>\
**Category:** Firmware\
**Created:** [October 4, 2020, 4:09pm UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949 "2020-10-04T16:09:11Z")\
**Posts on this page:** 12\
**Page:** 1

<div class="post-metadata">

**Author:** ![Tino52](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/tino52/32/16619_2.png) [@Tino52](https://community.particle.io/u/Tino52)\
**Post date:** [October 4, 2020, 4:09pm UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949/1 "2020-10-04T16:09:11Z")

</div>

Hello  
At regular times the display shows values that are not real it almost seems that the Particle.subscribe procedure does not find the data in the cloud.

One photons, with a dht22 and the command:  
void loop()  
Particle.publish (“Temp”, String (t), PRIVATE, NO\_ACK);  
Particle.publish (“Umi”, String (h) + “%”, PRIVATE, NO\_ACK); in the void loop

* * *

A Argon with a oled display (SSD1306) and the following command:  
void setup()  
Particle.subscribe (“Temp”, tempHandler, MY\_DEVICES);  
Particle.subscribe (“Umi”, umiHandler, MY\_DEVICES);

void tempHandler (const char \* event, const char \* data)  
{  
Temp = atoi (date);  
display.clearDisplay ();  
display.setTextSize (1);  
display.setTextColor (WHITE);  
display.setCursor (0,0);  
display.println (Time);  
display.setCursor (0.20);  
display.print (“Temp:”); display.println (Temp);}

* * *

void umiHandler (const char \* event, const char \* data)  
{  
Umi = atoi (date);  
display.setCursor (0.30);  
display.print (“Umi:”); display.println (Umi);  
display.display ();  
}

---

<div class="post-metadata">

**Author:** ![ScruffR](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/scruffr/32/6952_2.png) [@ScruffR](https://community.particle.io/u/ScruffR)\
**Post date:** [October 4, 2020, 6:23pm UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949/2 "2020-10-04T18:23:15Z")

</div>

You are writing `atoi(date)` but the parameter you receive from the function call is `data`.  
You should also not write `display.println(Time)` since `Time` is a device OS object and you shouldn’t reuse that variable name for anything else.

And another hint you definitly haven’t heard the first time: “Don’t use `String`, whenever you can avoid to” 😉

BTW, since you are always publishing both readings at the same time, it would be better to package both readings in a single event.

---

<div class="post-metadata">

**Author:** ![Tino52](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/tino52/32/16619_2.png) [@Tino52](https://community.particle.io/u/Tino52)\
**Post date:** [October 4, 2020, 7:20pm UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949/3 "2020-10-04T19:20:34Z")

</div>

For now thanks, I changed atoi (data) and replaced display.println (Time) with display.println (Ora).  
Ora = Time.format ("% H:% M% d.% M.% Y")

The problem remains, now I have to commit to “it would be better to package both readings in a single event” spin my brain I’ll see if something comes out otherwise I’ll go back to ask the community for help.  
Regards Valentino

---

<div class="post-metadata">

**Author:** ![ScruffR](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/scruffr/32/6952_2.png) [@ScruffR](https://community.particle.io/u/ScruffR)\
**Post date:** [October 5, 2020, 12:14am UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949/4 "2020-10-05T00:14:03Z")

</div>

Can you elaborate on this statement?

> [@Tino52](#):
>
> At regular times the display shows values that are not real it almost seems that the Particle.subscribe procedure does not find the data in the cloud.

What _are_ these regular intervals? Minutes, hours, days?  
In what way are the values "not real"?

Also, `Particle.subscribe()` does not get triggered when there is no triggering event, but once it _is_ triggered it will not need to _"find"_ the data but the data is _delivered_ to the function - meaning when the handler is called then definitely the data will be there too.

With regards to unifying the data into one event

publish

```cpp
  char data[32];
  snprintf(data, sizeof(data), "temp:%d,umi:%d", t, h);
  Particle.publish("dhtData", data, PRIVATE, NO_ACK);

```

subscribe

```cpp
  Particle.subscribe("dhtData", dataHandler, MY_DEVICES);
...
void dataHandler(const char *event, const char *data) {
  int t, h;

  // try parsing for two integers
  if (sscanf(data, "temp:%d,umi:%d", &t, &h) == 2) {
    // display your data
  }
}

```

Or you could use [JSON](https://docs.particle.io/reference/device-os/firmware/photon/#json) format for the payload.

---

<div class="post-metadata">

**Author:** ![Tino52](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/tino52/32/16619_2.png) [@Tino52](https://community.particle.io/u/Tino52)\
**Post date:** [October 5, 2020, 1:06pm UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949/5 "2020-10-05T13:06:18Z")

</div>

Hi @ScruffR  
after the suggested changes the data are these, not legible, they should be decimals. As you can see, they change from time to time. Coming soon I try the format the json procedures.

Temp:1077333196  
Umi:-1073741824  
Temp:1077339750  
Umi:1610612736  
Temp:1077333196  
Umi:-1073741824  
Temp:1077333196  
Umi:-1073741824  
Temp:1077339750  
Umi:1610612736  
Temp:1077333196  
Umi:-1073741824

---

<div class="post-metadata">

**Author:** ![ScruffR](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/scruffr/32/6952_2.png) [@ScruffR](https://community.particle.io/u/ScruffR)\
**Post date:** [October 5, 2020, 1:27pm UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949/6 "2020-10-05T13:27:00Z")

</div>

I guess the datatype don’t match then.  
Since you were using `atoi()` in your original code I deduced `t` and `h` should be `int` but if they were `float` or `double` that would explain what you’re seeing.

That’s why it’s always a good idea to provide all the relevant data and not let anything up to guessing 😉

BTW, how does the data sent via `Particle.publish()` look like in [console.particle.io](http://console.particle.io)?

For floating point values you’d do it like this

```cpp
void loop() {
  static uint32_t ms = 0;
  if (millis() - ms < 1000) return;
  ms = millis();
  
  float t = 12.3;
  float h = 34.5;
  
  char data[32];
  snprintf(data, sizeof(data), "temp:%.1f,umi:%.1f", t, h);
  Particle.publish("dhtData", data, PRIVATE, NO_ACK);
}

void dataHandler(const char *event, const char *data) {
  digitalWrite(D7, !digitalRead(D7));
  char sTemp[8];
  char sHum[8];
  float t, h;

  // try parsing for two strings not containing comma (floats are not directly supporte)
  if (sscanf(data, "temp:%[^,],umi:%[^,]", sTemp, sHum) == 2) {
    t = atof(sTemp);
    h = atof(sHum);
    Serial.printlnf("Temp = %.1f, Hum = %.1f", t, h);
  }
}

```

---

<div class="post-metadata">

**Author:** ![Tino52](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/tino52/32/16619_2.png) [@Tino52](https://community.particle.io/u/Tino52)\
**Post date:** [October 6, 2020, 5:15am UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949/7 "2020-10-06T05:15:42Z")

</div>

Good morning @ScruffR  
attached the result to the [console.particle.io](http://console.particle.io). The first is with my code, the second is with the one suggested by you, third result with particle.subscribe. I am also attaching the code as required (particle.pubish).  
Regards Valentino

My code (publish)on console result (photon)  
51.900002 %  
21.400000

Your code (publish) console result (photon)  
temp:1077293875,umi:1073741824

Result on Argon with particle.subscribe (your code)  
Temp:1077287321  
Umi:-1610612736  
Temp:1077293875  
Umi:1073741824  
Temp:1077287321  
Umi:-1610612736

```cpp
// This #include statement was automatically added by the Particle IDE.
#include <PietteTech_DHT.h>

#define DHTTYPE DHT22 // Sensor type DHT11/21/22/AM2301/AM2302
#define DHTPIN D6 // Digital pin for communications

 /*
  * NOTE: Use of callback_wrapper has been deprecated
  */
  //declaration
  //void dht_wrapper(); // must be declared before the lib initialization
  
 // Lib instantiate
PietteTech_DHT DHT(DHTPIN, DHTTYPE);
int n; // counter

//***Variabili temp e umi DHT22
double h = 0;
double t = 0;
//double f = 0;

// Orario
//String ora;

void setup()
{
  Serial.begin(9600);
Time.zone(+2);  
Particle.variable("Temp",t);
Particle.variable("Umi",h);        
  while (!Serial.available() && millis() < 30000) {
    	Serial.println("Press any key to start.");
    	Particle.process();
    	delay(1000);
  }
  Serial.println("DHT Simple program using DHT.acquireAndWait");
  Serial.print("LIB version: ");
  Serial.println(DHTLIB_VERSION);
  Serial.println("---------------");
  DHT.begin();
 }

/*
 * NOTE: Use of callback_wrapper has been deprecated but left in this example
 * to confirm backwards compabibility.
 */
 // This wrapper is in charge of calling
 // must be defined like this for the lib work
 //void dht_wrapper() {
 // DHT.isrCallback();
 //}

void loop()
{
Particle.connected();
  Serial.print("\n");
  Serial.print(n);
  Serial.print(": Retrieving information from sensor: ");
  Serial.println("Read sensor: ");
  DHT.acquireAndWait(1000); // wait up to 1 sec (default indefinitely)

  /*int result = DHT.acquireAndWait(1000); // wait up to 1 sec (default indefinitely)

  switch (result) {
  case DHTLIB_OK:
    Serial.println("OK");
    break;
  case DHTLIB_ERROR_CHECKSUM:
    Serial.println("Error\n\r\tChecksum error");
    break;
  case DHTLIB_ERROR_ISR_TIMEOUT:
    Serial.println("Error\n\r\tISR time out error");
    break;
  case DHTLIB_ERROR_RESPONSE_TIMEOUT:
    Serial.println("Error\n\r\tResponse time out error");
    break;
  case DHTLIB_ERROR_DATA_TIMEOUT:
    Serial.println("Error\n\r\tData time out error");
    break;
  case DHTLIB_ERROR_ACQUIRING:
    Serial.println("Error\n\r\tAcquiring");
    break;
  case DHTLIB_ERROR_DELTA:
    Serial.println("Error\n\r\tDelta time to small");
    break;
  case DHTLIB_ERROR_NOTSTARTED:
    Serial.println("Error\n\r\tNot started");
    break;
  default:
    Serial.println("Unknown error");
    break;
  }*/
  
  Serial.print("Humidity (%): ");
  h=DHT.getHumidity(), 2;
  Serial.println(DHT.getHumidity(), 2);

  Serial.print("Temperature (oC): ");
  t=DHT.getCelsius(), 2;
  Serial.println(DHT.getCelsius(), 2);
  n++;

// Mio codice
    //Particle.publish("Temp",String(t),PRIVATE,NO_ACK);
   // Particle.publish("Umi",String(h)+ " %",PRIVATE,NO_ACK);
        
    char data[32];
    snprintf(data, sizeof(data), "temp:%d,umi:%d", t, h);
    Particle.publish("dhtData", data, PRIVATE, NO_ACK);

//***    
    Serial.print("TempDHT: ");Serial.print(t);Serial.print(" ");Serial.print("Humid: );Serial.print(h);Serial.println("%");
    Serial.println("***");
    delay(2500);
}

```

---

<div class="post-metadata">

**Author:** ![ScruffR](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/scruffr/32/6952_2.png) [@ScruffR](https://community.particle.io/u/ScruffR)\
**Post date:** [October 6, 2020, 7:59am UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949/8 "2020-10-06T07:59:13Z")

</div>

You may have corrected the subscribe code, but your publish code is still taking the _wrong_ datatype.  
You need to correct that too.

This is the version meant for `int`

> [@Tino52](#):
>
> ` snprintf(data, sizeof(data), "temp:%d,umi:%d", t, h);`

This would be the one needed for floating point types

> [@ScruffR](#):
>
> `snprintf(data, sizeof(data), "temp:%.1f,umi:%.1f", t, h);`

---

<div class="post-metadata">

**Author:** ![Tino52](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/tino52/32/16619_2.png) [@Tino52](https://community.particle.io/u/Tino52)\
**Post date:** [October 6, 2020, 6:07pm UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949/9 "2020-10-06T18:07:30Z")

</div>

Hello @ScruffR finally I was able to see concrete data. Without your your suggestions and help I would not have succeeded.  
I enclose the important parts so that those who need them can find an answer.  
Best Regards e Grazie Mille!

Role particle.publish

```auto
char data[32];
snprintf(data, sizeof(data), "temp:%f,umi:%f", t, h);
Particle.publish("dhtData", data, PRIVATE, NO_ACK);   
delay(500);

```

Role particle.subscribe display to a OLED SSD1306

```auto
void setup(){
Particle.subscribe("dhtData", dataHandler, MY_DEVICES);
}
void dataHandler(const char *event, const char *data) {
  char sTemp[8];
  char sHum[8];
  float t, h;

  // try parsing for two strings not containing comma (floats are not directly supporte)
  if (sscanf(data, "temp:%[^,],umi:%[^,]", sTemp, sHum) == 2) {
    t = atof(sTemp);
    h = atof(sHum);
     display.clearDisplay();
    display.setTextSize(1);
    display.setTextColor(WHITE);
    display.setCursor(0,0);
    display.print("Temp & Umi Rodifiesso");
    display.setCursor(0,20);
    display.println(Ora);
    display.println(" ");
    display.setCursor(0,30);
    display.print("Temp:");display.println(t);
    display.print("Umi:");display.println(h);
    display.display();
Serial.printlnf("Temp = %.1f, Hum = %.1f", t, h);
  }
}

```

---

<div class="post-metadata">

**Author:** ![ScruffR](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/scruffr/32/6952_2.png) [@ScruffR](https://community.particle.io/u/ScruffR)\
**Post date:** [October 6, 2020, 7:43pm UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949/10 "2020-10-06T19:43:47Z")

</div>

Prego!

un punto in più

I’m pretty sure you can use `printlnf()` for `display` too ans since you are not using `t` & `h` anywhere else than to print the values, you can also drop the `atof()` and write it like this  
e.g.

```cpp
  display.printlnf("Temp: %s \r\nUmi: %s", sTemp, sHum);

```

Or when you already send the text as you want it printed, you could drop `sscanf()` to and just write `display.println(data)`.

---

<div class="post-metadata">

**Author:** ![Tino52](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/tino52/32/16619_2.png) [@Tino52](https://community.particle.io/u/Tino52)\
**Post date:** [October 7, 2020, 5:55am UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949/11 "2020-10-07T05:55:55Z")

</div>

Thanks I will treasure your suggestions same the last, I still have to add some text that will tell me the status of the humidifier fan that I control remotely. Now I have to assemble everything because these routines I needed for a remote command (via html) already working but without indications of temp and humidity.  
Regards Valentino

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/particle/original/3X/3/2/3291e3c9351789fe8620ae5bcec8d3fec67ff221.png) [@system](https://community.particle.io/u/system)\
**Post date:** [April 7, 2021, 5:56pm UTC](https://community.particle.io/t/particle-publish-particle-subscribe/57949/12 "2021-04-07T17:56:05Z")

</div>

Closed on April 7, 2021, 5:56pm UTC

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