Abstandssensor/Abstandssensor.ino

#include <WiFi.h>

#include <NeoPixelBus.h>
#include <NeoPixelSegmentBus.h>
#include <NeoPixelAnimator.h>
#include <NeoPixelBrightnessBus.h>

#include <MQTTPubSubClient.h>

#include "config.h"

// Only for ESP8266 D1 Mini
#define ECHO 5      // D1
#define TRIG 16     // D0
#define POTI_IN 17  // A0, analog In

WiFiClient client;
MQTTPubSubClient mqtt;

// Set Data pin for LED ring (we use GPIO3, which is also RX of the serial line)
#define DATA_PIN 3
const uint16_t PixelCount =  8;
NeoPixelBus<NeoGrbFeature, NeoEsp8266Dma800KbpsMethod> strip(PixelCount, DATA_PIN);

long duration;  // here we measure the time needed by the ultrasonic pulse
float distance; // the calculated distance

int poti;       // used to adjust the distance for yellow/red
int percent=0;  // will be used to calculate the current percentage of the distance reached

int colorSaturation=255;  // max color saturation for the colors (=brightness)

// define some colors we use later
RgbColor red(colorSaturation, 0, 0);
RgbColor green(0, colorSaturation, 0);
RgbColor yellow(colorSaturation, colorSaturation, 0);
RgbColor blue(0, 0, colorSaturation);
RgbColor white(colorSaturation);
RgbColor black(0);

void setup() {

    // start your network
    WiFi.begin(wifi_ssid, wifi_password);
    // connect to host
    client.connect(mqtt_server, 1883);
    // initialize mqtt client
    mqtt.begin(client);
    // connect to mqtt broker
    mqtt.connect("arduino", "public", "public");

    // subscribe topic and callback which is called when /hello has come
    mqtt.subscribe("/hello", [](const String& payload, const size_t size) {
        Serial.print("/hello ");
        Serial.println(payload);
    });

  // Setup the ultrasonic sensor PIN
  pinMode(TRIG, OUTPUT);  // TRIG-Pin: Output
  pinMode(ECHO, INPUT);   // ECHO-Pin: Input

  // Important to first initilizate Serial before the strip as
  // we are useing the RX PIN to connect the strip
  Serial.begin(9600);   // Baudrate: 115200
 
  // this resets all the neopixels to an off state
  strip.Begin();
  for(int i=0; i<PixelCount; i++) {strip.SetPixelColor(i, red);}
  strip.Show();

}

void setColor(RgbColor c) {
  for(int i=0; i<PixelCount; i++) {
    strip.SetPixelColor(i, c);
  }
  strip.Show();
}

void setRed() {
  setColor(red);
}

void setYellow() {
  setColor(yellow);
}

void setGreen() {
  setColor(green);
}

void loop() {


  // Read poti (Value range 16 - 1024)
  poti=analogRead(POTI_IN);

  // Measure Distance
  digitalWrite(TRIG, LOW);  delayMicroseconds(2);

  // TRIG-Pin ist HIGH für 10 Microsekunden
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);
  
  // Liest das ECHO aus und speichert die Zeit von Senden / Empfangen in Microsekunden
  duration = pulseIn(ECHO, HIGH);
  
  // Berechnung der Entfernung
  // Da der Weg doppel ist: Hinweg - Rückweg, muss der Wert durch 2 geteilt werden
  distance = duration * 0.034 / 2;

  // Set color depending on poti
  // We assume poti value/20 (resulting in range <1,5 cm - 100cm)
  // Green if we are more than 50% above goal, yellow below 50% of goal, red at or below goal
   
  percent=distance/((float)poti/10)*100;

  if      (percent >150) { setGreen(); }
  else if (percent >100) { setYellow(); }
  else {setRed(); }
  
  // Anzeige der Entfernung im seriellen Monitor
  #ifdef DEBUG
  Serial.println("Poti: " + String(poti));
  Serial.println("Entfernung: " + String(distance) + "cm");
  Serial.println("Percent: " + String(percent) + " of goal value");
  #endif
  delay(100);
  
}