// Example testing sketch for various DHT humidity/temperature sensors written by ladyada
// REQUIRES the following Arduino libraries:
// - DHT Sensor Library: https://github.com/adafruit/DHT-sensor-library
// - Adafruit Unified Sensor Lib: https://github.com/adafruit/Adafruit_Sensor
#include <DHT.h>
#include <WiFi.h>
#include <PubSubClient.h>
#define DHTPIN 4 // Digital pin connected to the DHT sensor
// Feather HUZZAH ESP8266 note: use pins 3, 4, 5, 12, 13 or 14 --
// Pin 15 can work but DHT must be disconnected during program upload.
// Uncomment whatever type you're using!
//#define DHTTYPE DHT11 // DHT 11
#define DHTTYPE DHT22 // DHT 22 (AM2302), AM2321
//#define DHTTYPE DHT21 // DHT 21 (AM2301)
// Connect pin 1 (on the left) of the sensor to +5V
// NOTE: If using a board with 3.3V logic like an Arduino Due connect pin 1
// to 3.3V instead of 5V!
// Connect pin 2 of the sensor to whatever your DHTPIN is
// Connect pin 4 (on the right) of the sensor to GROUND
// Connect a 10K resistor from pin 2 (data) to pin 1 (power) of the sensor
// Initialize DHT sensor.
// Note that older versions of this library took an optional third parameter to
// tweak the timings for faster processors. This parameter is no longer needed
// as the current DHT reading algorithm adjusts itself to work on faster procs.
DHT dht(DHTPIN, DHTTYPE);
//Wifi credential
const char *ssid="Wokwi-GUEST";
const char *password = "";
#define TOKEN "eKbdYrzGwOw3zOP2uo7Y"
//const char *mqtt_server = "thingsboard.cloud";
const char *mqtt_server = "demo.thingsboard.io";
WiFiClient wifiClient;
PubSubClient client(wifiClient);
int status = WL_IDLE_STATUS;
void setup() {
Serial.begin(115200);
Serial.println(F("DHTxx test!"));
dht.begin();
Serial.println("connect to : ");
Serial.println(ssid);
WiFi.begin(ssid,password);
while(WiFi.status() != WL_CONNECTED)
{
delay(500);
Serial.println("... ");
}
Serial.println("\n");
Serial.println("IP Address : ");
Serial.println(WiFi.localIP());
Serial.println("\n");
Serial.println("connect to : ");
Serial.println(ssid);
client.setServer(mqtt_server,1883);
}
void loop() {
// Wait a few seconds between measurements.
if(!client.connected()) reconnect();
// Reading temperature or humidity takes about 250 milliseconds!
// Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
float h = dht.readHumidity();
// Read temperature as Celsius (the default)
float t = dht.readTemperature();
// Read temperature as Fahrenheit (isFahrenheit = true)
float f = dht.readTemperature(true);
// Check if any reads failed and exit early (to try again).
if (isnan(h) || isnan(t) || isnan(f)) {
Serial.println(F("Failed to read from DHT sensor!"));
return;
}
// Compute heat index in Fahrenheit (the default)
float hif = dht.computeHeatIndex(f, h);
// Compute heat index in Celsius (isFahreheit = false)
float hic = dht.computeHeatIndex(t, h, false);
Serial.print(F("Humidity: "));
Serial.print(h);
Serial.print(F("% Temperature: "));
Serial.print(t);
Serial.print(F("°C "));
Serial.print(f);
Serial.print(F("°F Heat index: "));
Serial.print(hic);
Serial.print(F("°C "));
Serial.print(hif);
Serial.println(F("°F"));
String payload = "{";
payload += "\"Humidity\":";
payload += h;
payload += ",\"TemperatureC\":";
payload += t;
payload += ",\"TemperatureF\":";
payload += f;
payload += ",\"HeatIndexC\":";
payload += hic;
payload += ",\"HeatIndexF\":";
payload += hif;
payload += "}";
Serial.println(payload);
char attributes[1000];
payload.toCharArray(attributes,1000);
client.publish("v1/devices/me/telemetry",attributes);
client.publish("v1/devices/me/attributes",attributes);
Serial.println(attributes);
delay(5000);
}
void reconnect()
{
while(!client.connected())
{
status = WiFi.status();
if(status != WL_CONNECTED)
{
WiFi.begin(ssid,password);
while(WiFi.status() != WL_CONNECTED)
{
delay(500);
Serial.println(". ");
}
Serial.println("Connected to AP");
}
Serial.println("Connecting to thingsboard node ..." );
if(client.connect("ea2c58a0-6dbf-11ee-9d7d-a533898c4c2a",TOKEN,""))
{
Serial.println(("Done"));
}
else
{
Serial.println("FAILED, retrying in 5 seconds");
delay(5000);
}
}
}