S21vEnQ7

1#include <DHT.h>
2#include <DHT_U.h>
3#include <ESP8266WiFi.h>
4#include <ESP8266WebServer.h>
5#include <SDS011.h>
6#include <SoftwareSerial.h>
7
8
9#define SDS_RX D1
10#define SDS_TX D2
11
12#define DHTPIN D4 
13#define DHTTYPE DHT22   
14
15const char* ssid     = "wifi-ssid";
16const char* password = "password";
17const char* host = "api.thingspeak.com";
18String apiKey = ""; // thingspeak.com api key goes here
19
20float p10,p25;
21int error;
22
23struct Air {
24  float pm25;
25  float pm10;
26  float humidity;
27  float temperature;
28};
29
30
31DHT_Unified dht(DHTPIN, DHTTYPE);
32ESP8266WebServer server(80);
33WiFiClient client;
34SDS011 sds;
35
36void setup() {
37  Serial.begin(9600);
38  sds.begin(SDS_RX,SDS_TX);
39  dht.begin();
40  connectToWiFi();
41}
42
43void loop() {
44  Air airData = readPolution();
45  if (client.connect(host,80) & airData.pm25 > 0.0) {
46    String postStr = apiKey;
47    postStr +="&field1=";
48    postStr += String(airData.pm25);
49    postStr +="&field2=";
50    postStr += String(airData.pm10);
51    postStr +="&field3=";
52    postStr += String(airData.humidity);
53    postStr +="&field4=";
54    postStr += String(airData.temperature);
55    postStr += "\r\n\r\n";
56  
57    client.print("POST /update HTTP/1.1\n");
58    client.print("Host: api.thingspeak.com\n");
59    client.print("Connection: close\n");
60    client.print("X-THINGSPEAKAPIKEY: "+apiKey+"\n");
61    client.print("Content-Type: application/x-www-form-urlencoded\n");
62    client.print("Content-Length: ");
63    client.print(postStr.length());
64    client.print("\n\n");
65    client.print(postStr);
66  }
67  client.stop();
68  delay(15000);
69  
70  server.handleClient();
71}
72
73void connectToWiFi(){
74  WiFi.mode(WIFI_STA);
75  WiFi.begin(ssid, password);
76 
77  Serial.print("Connecting to ");
78  Serial.println(ssid); 
79
80  while (WiFi.status() != WL_CONNECTED) {
81    delay(500);
82    Serial.print(".");
83  }
84
85  Serial.println("");
86  Serial.println("WiFi connected");  
87  Serial.println("IP address: ");
88  Serial.println(WiFi.localIP());
89  startServer();
90}
91
92void startServer(){
93  server.on("/", handleRoot);
94  server.begin();
95  Serial.println("HTTP server started");
96}
97
98void handleRoot() {
99    Air airData = readPolution();
100    server.send(200, "text/plain", "PM2.5: " + String(airData.pm25) + " (" + String(calculatePolutionPM25(airData.pm25)) + "% normy) | PM10: " +  String(airData.pm10) + " (" + String(calculatePolutionPM10(airData.pm10)) + "% normy) | Temperature: " + airData.temperature + " | Humidity: " + airData.humidity);  
101}
102
103Air readPolution(){
104  float temperature, humidity;
105  error = sds.read(&p25,&p10);
106  if (!error) {
107    sensors_event_t event;  
108    dht.temperature().getEvent(&event);
109    if (isnan(event.temperature)) {
110      Serial.println("Error reading temperature!");
111    } else {
112      temperature = event.temperature;
113    }
114  
115    dht.humidity().getEvent(&event);
116    if (isnan(event.relative_humidity)) {
117      Serial.println("Error reading humidity!");
118    } else {
119      humidity = event.relative_humidity;
120    }
121   
122    Air result = (Air){normalizePM25(p25/10, humidity), normalizePM10(p10/10, humidity), humidity, temperature};
123    return result;
124  } else {
125    Serial.println("Error reading SDS011");
126    return (Air){0.0, 0.0, 0.0, 0.0};
127  }
128}
129
130//Correction algorythm thanks to help of Zbyszek Kiliański (Krakow Zdroj)
131float normalizePM25(float pm25, float humidity){
132  return pm25/(1.0+0.48756*pow((humidity/100.0), 8.60068));
133}
134
135float normalizePM10(float pm10, float humidity){
136  return pm10/(1.0+0.81559*pow((humidity/100.0), 5.83411));
137}
138
139float calculatePolutionPM25(float pm25){
140  return pm25*100/25;
141}
142
143float calculatePolutionPM10(float pm10){
144  return pm10*100/50;
145}