smarthome-presence-detect/arduino/wlan_ultraschall/wlan_ultraschall.ino

#include <ESP8266WiFi.h>
#include <PubSubClient.h>

const char* SSID = "smartroom";
const char* PSK = "smarthome";
const char* MQTT_BROKER = "192.168.4.1";
WiFiClient espClient;
PubSubClient client(espClient);

// defines pins numbers
const int trigPin = 2;  //D4
const int echoPin = 0;  //D3

long duration;
int distance;
int distance_alt=0;
char msg[50];
int value = 0;
long lastMsg = 0;

void setup() {
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input

  Serial.begin(115200);
  setup_wifi();
  client.setServer(MQTT_BROKER, 1883);
}

void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(SSID);
  WiFi.mode(WIFI_STA);
  WiFi.begin(SSID, PSK);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void reconnect() {
    while (!client.connected()) {
        Serial.print("Reconnecting...");
        if (!client.connect("ESP8266Client")) {
            Serial.print("failed, rc=");
            Serial.print(client.state());
            Serial.println(" retrying in 5 seconds");
            delay(5000);
        }
    }
}


void loop() {
  
    if (!client.connected()) {
        reconnect();
    }
    client.loop();
 
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);

  // Calculating the distance
  distance = duration * 0.034 / 2;
  // Prints the distance on the Serial Monitor
  if((distance!=(distance_alt-1))&&(distance!=(distance_alt))&&(distance!=(distance_alt+1))){//+-1 um störungen herauszufiltern
    snprintf (msg,50,"%d", distance);
    Serial.print("Publish Motion: ");
    Serial.println(msg);
    client.publish("/home/data", msg);
    delay(500);
  }
  distance_alt=distance;
}