airquality.ino

/*
 Adapted from example file at https://github.com/espressif/arduino-esp32/blob/master/libraries/WiFiClientSecure/examples/WiFiClientSecure/WiFiClientSecure.ino
 by Evandro Copercini - Apache 2.0 License.
*/

#include <WiFiClientSecure.h>
#include <ArduinoJson.h>
#include <ESP32Servo.h>

Servo myservo;  // create servo object to control a servo
// 16 servo objects can be created on the ESP32

int pos = 0;    // variable to store the servo position
int servoPin = 13;

const char* ssid     = "HH-1B";     // your network SSID (name of wifi network)
const char* password = "HaHoForward"; // your network password

//nox scale -- 0 =0 deg
// 40 = 180 deg (legal limit)
// == conversion = * 4.5


const char*  server = "opendata.bristol.gov.uk";  // Server URL

const char* test_root_ca= \
     "-----BEGIN CERTIFICATE-----\n" \
     "MIIEkjCCA3qgAwIBAgIQCgFBQgAAAVOFc2oLheynCDANBgkqhkiG9w0BAQsFADA/\n" \
     "MSQwIgYDVQQKExtEaWdpdGFsIFNpZ25hdHVyZSBUcnVzdCBDby4xFzAVBgNVBAMT\n" \
     "DkRTVCBSb290IENBIFgzMB4XDTE2MDMxNzE2NDA0NloXDTIxMDMxNzE2NDA0Nlow\n" \
     "SjELMAkGA1UEBhMCVVMxFjAUBgNVBAoTDUxldCdzIEVuY3J5cHQxIzAhBgNVBAMT\n" \
     "GkxldCdzIEVuY3J5cHQgQXV0aG9yaXR5IFgzMIIBIjANBgkqhkiG9w0BAQEFAAOC\n" \
     "AQ8AMIIBCgKCAQEAnNMM8FrlLke3cl03g7NoYzDq1zUmGSXhvb418XCSL7e4S0EF\n" \
     "q6meNQhY7LEqxGiHC6PjdeTm86dicbp5gWAf15Gan/PQeGdxyGkOlZHP/uaZ6WA8\n" \
     "SMx+yk13EiSdRxta67nsHjcAHJyse6cF6s5K671B5TaYucv9bTyWaN8jKkKQDIZ0\n" \
     "Z8h/pZq4UmEUEz9l6YKHy9v6Dlb2honzhT+Xhq+w3Brvaw2VFn3EK6BlspkENnWA\n" \
     "a6xK8xuQSXgvopZPKiAlKQTGdMDQMc2PMTiVFrqoM7hD8bEfwzB/onkxEz0tNvjj\n" \
     "/PIzark5McWvxI0NHWQWM6r6hCm21AvA2H3DkwIDAQABo4IBfTCCAXkwEgYDVR0T\n" \
     "AQH/BAgwBgEB/wIBADAOBgNVHQ8BAf8EBAMCAYYwfwYIKwYBBQUHAQEEczBxMDIG\n" \
     "CCsGAQUFBzABhiZodHRwOi8vaXNyZy50cnVzdGlkLm9jc3AuaWRlbnRydXN0LmNv\n" \
     "bTA7BggrBgEFBQcwAoYvaHR0cDovL2FwcHMuaWRlbnRydXN0LmNvbS9yb290cy9k\n" \
     "c3Ryb290Y2F4My5wN2MwHwYDVR0jBBgwFoAUxKexpHsscfrb4UuQdf/EFWCFiRAw\n" \
     "VAYDVR0gBE0wSzAIBgZngQwBAgEwPwYLKwYBBAGC3xMBAQEwMDAuBggrBgEFBQcC\n" \
     "ARYiaHR0cDovL2Nwcy5yb290LXgxLmxldHNlbmNyeXB0Lm9yZzA8BgNVHR8ENTAz\n" \
     "MDGgL6AthitodHRwOi8vY3JsLmlkZW50cnVzdC5jb20vRFNUUk9PVENBWDNDUkwu\n" \
     "Y3JsMB0GA1UdDgQWBBSoSmpjBH3duubRObemRWXv86jsoTANBgkqhkiG9w0BAQsF\n" \
     "AAOCAQEA3TPXEfNjWDjdGBX7CVW+dla5cEilaUcne8IkCJLxWh9KEik3JHRRHGJo\n" \
     "uM2VcGfl96S8TihRzZvoroed6ti6WqEBmtzw3Wodatg+VyOeph4EYpr/1wXKtx8/\n" \
     "wApIvJSwtmVi4MFU5aMqrSDE6ea73Mj2tcMyo5jMd6jmeWUHK8so/joWUoHOUgwu\n" \
     "X4Po1QYz+3dszkDqMp4fklxBwXRsW10KXzPMTZ+sOPAveyxindmjkW8lGy+QsRlG\n" \
     "PfZ+G6Z6h7mjem0Y+iWlkYcV4PIWL1iwBi8saCbGS5jN2p8M+X+Q7UNKEkROb3N6\n" \
     "KOqkqm57TH2H3eDJAkSnh6/DNFu0Qg==\n" \
     "-----END CERTIFICATE-----\n";

WiFiClientSecure client;

void setup() {
  //Initialize serial and wait for port to open:
  Serial.begin(115200);
  delay(100);

  myservo.setPeriodHertz(50);    // standard 50 hz servo
  myservo.attach(servoPin, 500, 2500); // attaches the servo on pin 18 to the servo object
  myservo.write(0);


}

void loop() {
  Serial.print("Attempting to connect to SSID: ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
 // attempt to connect to Wifi network:
 int timer = 0;
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    // wait 1 second for re-trying
    delay(1000);
    timer++;
    if (timer > 120) { break; }
  }

  Serial.print("Connected to ");
  Serial.println(ssid);

  client.setCACert(test_root_ca);

  Serial.println("\nStarting connection to server...");
  if (!client.connect(server, 443))
    Serial.println("Connection failed!");
  else {
    Serial.println("Connected to server!");
    // Make a HTTP request:
      client.print((String)"GET /api/records/1.0/search/?dataset=air-quality-data-continuous&rows=1&sort=date_time&facet=date_time&facet=location&facet=current&refine.location=AURN+St+Pauls HTTP/1.1\r\n" +
               "Host: " + String(server) + "\r\n" +
               "Connection: close\r\n\r\n");


    while (client.connected()) {
      String line = client.readStringUntil('\n');
      if (line == "\r") {
        Serial.println("headers received");
        break;
      }
    }
    // if there are incoming bytes available
    // from the server, read them and print them:
    String line = "";
    while (client.available()) {
         line = client.readStringUntil('\r');
         Serial.println(line);
         if (line.indexOf('{')>=0) {
         Serial.println("parsingValues"); 
         DynamicJsonDocument json_doc(6000);
         DeserializationError json_error = deserializeJson(json_doc, line);
         if (json_error) { 
           Serial.println("parseing failed");
           Serial.println(json_error.c_str());
         } 
         else {
      
         Serial.println("Nox");
         String no2=json_doc["records"][0]["fields"]["no2"];
         Serial.println(no2);
         myservo.write(min(no2.toFloat()*4.5,180.0));
      
      // Extract the data here
        
      
         }
         }
    }

    client.stop();
  }

  WiFi.disconnect(true);
  delay(60000);
}