D1 Mini with DHT22+MQTT
Posted: Fri Jun 26, 2020 11:24 amHi to all,
I have setup a DHT22 on a D1 Mini which reports the information via MQTT to Home Assistant.
I have one issue and one question... Well I guess that makes it 2 questions.
1 - I power up and the temperature is showing 27C and Humidity is 37% which is about right. After a few days it reads a temperature of appr. 7C and humidity of appr 3%. Powering off for a few hours and back on brings back roughly the same bad numbers again. If I reflash the same program, I get the good results. I am hoping someone might be able to take a look at my code (a mixture of code I found here and there on the web as I am not fluent at this) and see if I can apply a fix.
2 - If I disconnect the device Home Assistant is still showing the last results so I have no way of knowing if the device is online or not. I am aware I can use a Last Will on MQTT but I cannot figure out how to go about it as the Will reports to its own topic but I would like if off line to show Offline in the place of the Temperature and Humidity numbers.
Here is my code:
I have setup a DHT22 on a D1 Mini which reports the information via MQTT to Home Assistant.
I have one issue and one question... Well I guess that makes it 2 questions.
1 - I power up and the temperature is showing 27C and Humidity is 37% which is about right. After a few days it reads a temperature of appr. 7C and humidity of appr 3%. Powering off for a few hours and back on brings back roughly the same bad numbers again. If I reflash the same program, I get the good results. I am hoping someone might be able to take a look at my code (a mixture of code I found here and there on the web as I am not fluent at this) and see if I can apply a fix.
2 - If I disconnect the device Home Assistant is still showing the last results so I have no way of knowing if the device is online or not. I am aware I can use a Last Will on MQTT but I cannot figure out how to go about it as the Will reports to its own topic but I would like if off line to show Offline in the place of the Temperature and Humidity numbers.
Here is my code:
Code: Select all
#include <ESP8266WiFi.h>
#include <PubSubClient.h>
#include "DHTesp.h"
DHTesp dht;
#define wifi_ssid "**"
#define wifi_password "**"
#define mqtt_server "172.16.0.125"
#define mqtt_user "**"
#define mqtt_password "**"
#define temperature_topic "sensor/temperature1" //Office
#define humidity_topic "sensor/humidity1"
char message_buff[100];
long lastMsg = 0;
long lastRecu = 0;
bool debug = false; //Display log message if True
WiFiClient espClient;
PubSubClient client(espClient);
void setup() {
Serial.begin(9600);
setup_wifi();
client.setServer(mqtt_server, 1883);
dht.setup(4, DHTesp::DHT22);
pinMode(2,OUTPUT);
}
void setup_wifi() {
delay(10);
Serial.println();
Serial.print("Connecting to ");
Serial.println(wifi_ssid);
WiFi.begin(wifi_ssid, wifi_password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi OK ");
Serial.print("=> ESP8266 IP address: ");
Serial.println(WiFi.localIP());
}
void reconnect() {
while (!client.connected()) {
Serial.print("Connecting to MQTT broker ...");
if (client.connect("ESP8266Client", mqtt_user, mqtt_password)) {
Serial.println("OK");
} else {
Serial.print("Error : ");
Serial.print(client.state());
Serial.println(" Wait 5 seconds before retry");
delay(5000);
}
}
}
void loop() {
if (!client.connected()) {
reconnect();
}
client.loop();
long now = millis();
if (now - lastMsg > 1000 * 60) {
lastMsg = now;
int h = round(dht.getHumidity());
int t = round(dht.getTemperature());
if (debug) {
Serial.print("Temperature : ");
Serial.print(t);
Serial.print(" | Humidity : ");
Serial.println(h);
}
digitalWrite(2,HIGH);
client.publish(temperature_topic, String(t).c_str(), true); // Publish temperature
client.publish(humidity_topic, String(h).c_str(), true); // Publish humidity
delay(2000);
digitalWrite(2,LOW);
}
}