MQTT Temperature and Humidity Monitor for Home Assistant
This project was terribly straightforward - two elements area unit needed: Adafruit Feather HUZZAH with ESP8266 WAN
This sensing element looks to be a lot of correct than a budget DHT11 sensors. It additionally uses I2C that makes interfacing with it super easy!
it is very common for completely different and various levels to be at slightly different temperatures. so as to observe the temperature and wetness
Hardware Connections: above Circuit
Hardware components:
Adafruit HUZZAH ESP8266 Breakout
Adafruit Si7021 Temperature & Humidity Sensor Breakout Board
Software apps and online services
Arduino IDE
Home Assistant
code :
#include <PubSubClient.h>
#include <Adafruit_Si7021.h>
#include <ESP8266WiFi.h>
// Replace these with your WiFi credentials
const char* ssid = "getoffmylan";
const char* password = "correcthorsebatterystaple";
// Replace these with your MQTT connection info
const char* mqtt_server = "192.168.1.34";
const char* mqtt_user = "mqtt_username";
const char* mqtt_password = "mqtt_password";
// Define which MQTT topics the data is published to
#define humidity_topic "sensor/basement/humidity"
#define temperature_topic "sensor/basement/temperature"
WiFiClient espClient;
PubSubClient client(espClient);
Adafruit_Si7021 sensor;
void setup() {
// Configure the two LEDs
pinMode(0, OUTPUT);
pinMode(2, OUTPUT);
digitalWrite(0, LOW);
digitalWrite(2, HIGH);
Serial.begin(115200);
delay(100);
// We start by connecting to a WiFi network
Serial.println();
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
// Blink the LED until we're connected
int i = 0;
while (WiFi.status() != WL_CONNECTED) {
digitalWrite(0, i % 2);
delay(500);
Serial.print(".");
i++;
}
digitalWrite(0, LOW);
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
Serial.println("");
// Connect to MQTT
client.setServer(mqtt_server, 1883);
// Initiate the sensor
sensor = Adafruit_Si7021();
if (sensor.begin()) {
Serial.println('Sensor ready');
} else {
// TODO: We should probably reset the device if this happens
Serial.println('SENSOR FAILED TO START');
}
delay(50);
digitalWrite(0, LOW);
}
// Attempts to reconnect to MQTT if we're ever disconnected
void reconnect() {
// Loop until we're reconnected
while (!client.connected()) {
digitalWrite(0, HIGH);
Serial.print("Attempting MQTT connection...");
// Attempt to connect
if (client.connect("ESP8266Client", mqtt_user, mqtt_password)) {
Serial.println("connected");
digitalWrite(0, LOW);
} else {
Serial.print("failed, rc=");
Serial.print(client.state());
Serial.println(" try again in 5 seconds");
// Wait 5 seconds before retrying
delay(5000);
}
}
}
// Helps check whether any value change is significant enough to warrant a data push
bool checkBound(float newValue, float prevValue, float maxDiff) {
return !isnan(newValue) &&
(newValue < prevValue - maxDiff || newValue > prevValue + maxDiff);
}
long lastMsg = 0;
float temp = 0.0;
float hum = 0.0;
float diff = 0.1;
void loop() {
// Ensure we stay connected
if (!client.connected()) {
reconnect();
}
// Let MQTT do it's thing
client.loop();
digitalWrite(0, LOW);
bool sent = false;
// Check the temp and humidity once per second
long now = millis();
if (now - lastMsg > 1000) {
lastMsg = now;
// Read the values from the sensor
float newTemp = sensor.readTemperature();
float newHum = sensor.readHumidity();
// Check whether the temperature has changed
if (checkBound(newTemp, temp, diff)) {
temp = newTemp;
Serial.print("New temperature:");
Serial.println(String(temp).c_str());
client.publish(temperature_topic, String(temp).c_str(), true);
sent = true;
}
// Check whether the humidity has changed
if (checkBound(newHum, hum, diff)) {
hum = newHum;
Serial.print("New humidity:");
Serial.println(String(hum).c_str());
client.publish(humidity_topic, String(hum).c_str(), true);
sent = true;
}
// If any data was sent (due to a change) then blink the blue LED
if (sent) {
sent = false;
digitalWrite(2, LOW);
delay(300);
digitalWrite(2, HIGH);
}
}
}
Conclusions:
It solely have one amongst these running thus far, however it's going to produce many a lot of and unfold them throughout the house.
The HUZZAH board are often run from a LiPo battery which implies It may place this device anyplace with no need a USB wall wart. However, as a result of local area network could be a superpower drain, It got to modify the code to sleep itself and solely connect once a major temp/humidity amendment has been detected.
It may conjointly verify building some quite enclosure. The future step network module provides off heat although that may skew the info
