DS18B20 & Volkszähler

Statt mit einem Raspberry Pi kann man auch mit einem Wemos D1 Mini oder vergleichbarem die ausgelesene Temperatur eines DS18B20 Temperatursensors an eine Volkszähler Instanz schicken.

Benötigte Hardware:

• NodeMCU oder Wemos D1 Mini
• DS18B20
• 4,7 kOhm oder 10 kOhm Widerstand
• Breadboard
• Male – Female Jumper Wire oder Male -Male Jumper – Wire

Arduino Sketch:

#include <Arduino.h>
 #include <ESP8266WiFi.h>
 #include <ESP8266WiFiMulti.h>
 #include <ESP8266HTTPClient.h>
 #include <Wire.h>
 #include <SPI.h>
 #include <OneWire.h>
 #include <DallasTemperature.h>

#define SERIAL

const String host = "IP-Adresse-des-VZ";
 const unsigned int port = 80;

const String url_start = "/middleware.php/data/";
 const String url_stop = ".json?operation=add&value=";

const String uuid_temp = "UUID";

const unsigned char ONE_WIRE_BUS = D4;

OneWire oneWire(ONE_WIRE_BUS);
 DallasTemperature sensor(&oneWire);

byte maxwait = 120;

#define SEALEVELPRESSURE_HPA (1013.25)

ESP8266WiFiMulti WiFiMulti;

void setup() {
 #ifdef SERIAL
 Serial.begin(115200);
 Serial.println("BOOT");

Serial.print("Wifi...");
 #endif

sensor.begin();
 Serial.print("Anzahl Sensoren: ");
 Serial.println(sensor.getDeviceCount());

WiFiMulti.addAP("SSID", "Passwort");

#ifdef SERIAL
 Serial.println("OK");
 Serial.print("DS18B20");
 #endif

#ifdef SERIAL
 Serial.print("OK");
 #endif
 }
 bool waitWifi() {
 while((WiFiMulti.run() != WL_CONNECTED) & maxwait > 0) {
 #ifdef SERIAL
 Serial.println("Wait Wifi");
 #endif
 delay(1000);
 maxwait--;
 }

if(WiFiMulti.run() == WL_CONNECTED) return true;
 return false;
 }

void sendHttpData(String url) {
 HTTPClient http;

if(waitWifi()) {

#ifdef SERIAL
 Serial.print("GET: "); Serial.println(url);
 #endif
 http.begin(host, port, url); //HTTP
 int httpCode = http.GET();
 #ifdef SERIAL
 if(httpCode) {
 if(httpCode == 200) {
 String payload = http.getString();
 Serial.println(payload);
 }else{
 Serial.print("HTTP "); Serial.println(httpCode);
 }
 } else {
 Serial.print("[HTTP] GET... failed, no connection or no HTTP server\n");
 }
 #endif
 }else{
 #ifdef SERIAL
 Serial.print("No WiFi available\n");
 #endif
 }
 }

void loop() {

String url_temp = "";

#ifndef SERIAL
 digitalWrite(1, HIGH); //LED off
 #endif

delay(2000); //If we've just started the power might be somewhat distorted - lets wait a bit to get things setteled...

{
 sensor.requestTemperatures();
 float temperatur = sensor.getTempCByIndex(0);
 #ifdef SERIAL
 Serial.print("Temperature = ");
 Serial.println(temperatur);
 Serial.println(" *C");
 #endif
 url_temp = url_start;
 url_temp += uuid_temp;
 url_temp += url_stop;
 url_temp += (temperatur);

sendHttpData(url_temp);
 }

#ifdef SERIAL
 Serial.println("SLEEP");
 Serial.flush();
 #endif

}

Angepasst werden müssen:

• IP-Adresse
• WLAN Daten
• UUID-Temp

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