ESP8266 Community Forum

- Sun Mar 06, 2016 5:24 pm #42581 Hi,

I made a small project to have a battery operated ESP8266 (using Adafruit's Huzzah board) which reads temperature and humidity from a DHT22 sensor, it also reads the battery voltage using a simple voltage divider circuit wired to the analog IO pin of the ESP. The ESP will then connect to Adafruit's IO service and send it latest readings.
I am using a 3.7v Li-Ion battery wired to the VBAT+ pin of the huzzah board. To minimize battery load, I put a ESP.deepsleep() call at the end of my main loop.

This seemed to work fine at first, but I found that after x hours, the ESP would crash, in such a way that even pushing the reset button on the huzzah board would not help, I really had to remove/replug the battery before the ESP would start again correctly.

I had my laptop connector all the time so I had the logfile of what the ESP sent over its serial line, and I could see before it died, the readings from the DHT22 started being off.

See below a 'correct' loop followed by a 'faulty' loop:

Connecting to MQTT... MQTT Connected!
V: 3.32 | T: 18.40 | H: 50
Connecting to AP: -removed-......Failed
Connecting to AP: -removed-....
WiFi connected

Connecting to MQTT... MQTT Connected!
V: 3.31 | T: nan | H: 2147483647
Connecting to AP: -removed-......Failed
Connecting to AP: -removed-......Failed
Connecting to AP: -removed-......Failed
Connecting to AP: -removed-......Failed
Connecting to AP: -removed-......Failed
Connecting to AP: -removed-....
WiFi connected

As you can see the temperature becomes NaN, and the humidity is way off (should be between 0-100).

Anyone got any idea what this could be?

This is the code i'm using:

Code: Select all#include <Adafruit_MQTT_Client.h>
#include <Adafruit_MQTT.h>
#include <DHT.h>
#include <ThingSpeak.h>
#include <ESP8266WiFi.h>


//AP definitions
int status = WL_IDLE_STATUS;     // the Wifi radio's status

struct WifiConn
{
   char *Ssid;
   char *Password;
};

WifiConn APList[] = {
   {"-removed-", ""}
   ,{"-removed-", "-removed-"}
   ,{ "-removed-", "-removed-" }
   ,{ "-removed-", "-removed-" }
};

WiFiClient client;

/************************* Adafruit.io Setup *********************************/

#define AIO_SERVER      "io.adafruit.com"
#define AIO_SERVERPORT  1883                   // use 8883 for SSL
#define AIO_USERNAME    "-removed-"
#define AIO_KEY         "-removed-"

// Store the MQTT server, username, and password in flash memory.
// This is required for using the Adafruit MQTT library.
const char MQTT_SERVER[] PROGMEM = AIO_SERVER;
const char MQTT_USERNAME[] PROGMEM = AIO_USERNAME;
const char MQTT_PASSWORD[] PROGMEM = AIO_KEY;
// Setup the MQTT client class by passing in the WiFi client and MQTT server and login details.
Adafruit_MQTT_Client mqtt(&client, MQTT_SERVER, AIO_SERVERPORT, MQTT_USERNAME, MQTT_PASSWORD);


/****************************** Feeds ***************************************/

// Setup a feed called 'photocell' for publishing.
// Notice MQTT paths for AIO follow the form: <username>/feeds/<feedname>
const char TEMP_FEED[] PROGMEM = AIO_USERNAME "/feeds/esp8266-1-temp1";
Adafruit_MQTT_Publish TempFeed = Adafruit_MQTT_Publish(&mqtt, TEMP_FEED);

const char HUM_FEED[] PROGMEM = AIO_USERNAME "/feeds/esp8266-1-hum1";
Adafruit_MQTT_Publish HumFeed = Adafruit_MQTT_Publish(&mqtt, HUM_FEED);

const char VIN_FEED[] PROGMEM = AIO_USERNAME "/feeds/esp8266-1-vin1";
Adafruit_MQTT_Publish VinFeed = Adafruit_MQTT_Publish(&mqtt, VIN_FEED);

#define REPORT_INTERVAL 60 // in sec

#define DHTPIN 2
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);
float fOldTemp;
int iOldHum;


#define VOLTAGE_PIN A0
float fOldVoltage;


// Bug workaround for Arduino 1.6.6, it seems to need a function declaration
// for some reason (only affects ESP8266, likely an arduino-builder bug).
void MQTT_connect();

void setup() {

   Serial.begin(115200);
   Serial.println();
   while (WiFi.status() != WL_CONNECTED)
   {
      wifiConnect();
   }
   ThingSpeak.begin(client);
   fOldTemp = -1;
   fOldVoltage = -1;
   dht.begin();
   pinMode(VOLTAGE_PIN, INPUT);
   Serial.println("");
}

void loop() {

   MQTT_connect();

   float vout = analogRead(VOLTAGE_PIN) / 1024.0;
   float fVoltage = vout / 0.090909;

   float fTemp = dht.readTemperature();
   int iHum = dht.readHumidity();



   if ((fTemp != fOldTemp)
        || (iHum != iOldHum)
        || (fVoltage != fOldVoltage))
   {
      SendData(fTemp, fVoltage, iHum);
      fOldTemp = fTemp;
      Serial.print("V: ");
      Serial.print(fVoltage);
      Serial.print(" | T: ");
      Serial.print(fTemp);
      Serial.print(" | H: ");
      Serial.println(iHum);
   }

   int cnt = REPORT_INTERVAL;

   ESP.deepSleep(REPORT_INTERVAL * 1000000, WAKE_RF_DEFAULT);
}

void wifiConnect()
{
   for (auto& AP : APList)
   {
      int iConnTries = 0;
      Serial.print("Connecting to AP: ");
      Serial.print(AP.Ssid);
     
      WiFi.begin(AP.Ssid, AP.Password);
      while (WiFi.status() != WL_CONNECTED && iConnTries <= 5) {
         delay(1000);
         Serial.print(".");
         iConnTries++;
      }
      if (WiFi.status() != WL_CONNECTED)
      {
         Serial.println("Failed");
      }
      else
      {
         Serial.println("");
         Serial.println("WiFi connected");
         return;
      }
   }
}

void SendData(float temp, float voltage, int iHum)
{
   TempFeed.publish(temp);
   VinFeed.publish(voltage);
   HumFeed.publish(iHum);
}

// Function to connect and reconnect as necessary to the MQTT server.
// Should be called in the loop function and it will take care if connecting.
void MQTT_connect() {
   int8_t ret;

   // Stop if already connected.
   if (mqtt.connected()) {
      return;
   }

   Serial.print("Connecting to MQTT... ");

   uint8_t retries = 3;
   while ((ret = mqtt.connect()) != 0) { // connect will return 0 for connected
      Serial.println(mqtt.connectErrorString(ret));
      Serial.println("Retrying MQTT connection in 5 seconds...");
      mqtt.disconnect();
      delay(5000);  // wait 5 seconds
      retries--;
      if (retries == 0) {
         // basically die and wait for WDT to reset me
         while (1);
      }
   }
   Serial.println("MQTT Connected!");
}

- Wed Jan 11, 2017 8:52 am #60837 Ive heard that sending NaN can create problems. not sure this is correct for your thingspeak etc. i check for NaN when reading sensor, and set it to a default (1) if it is a NaN, so i can usually detect it.

i do have the same problem of crashing with adafruit.io as MQTT broker though, so if you find something out: please post!

/A