EMonitor — ESP32 based Environment Monitoring Device with Flask Server

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1void loop{
2            //calculate readings and create CAP MSG
3            if (WiFi.status() != WL_CONNECTED)
4            {
5                //if not connected, try to connect to WiFi in each loop iteration
6                bool connected = connect_to_wifi();
7                if (connected){
8                        //send MSG to server
9                }
10                else{
11                        //buffer MSG
12                }
13        }
14            else{
15                //send MSG to server
16            }
17    }
18​
19    bool connect_to_wifi(){
20            WiFi.begin(SSID,PW) //begin the wifi connection
21            if (WiFi.status() == WL_CONNECTED)
22            {
23                return truue;
24            }
25            else{
26                return false;
27            }
28    }

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1queue<String> buffer_identifier;
2    queue<String> buffer_datetime;
3    queue<int> buffer_msg_ids;
4​
5    //mean buffers
6    queue<double> buffer_t;
7    queue<double> buffer_h;
8    queue<double> buffer_p;
9    queue<double> buffer_l;
10​
11    //sd buffers
12    queue<double> buffer_t_;
13    queue<double> buffer_h_;
14    queue<double> buffer_p_;
15    queue<double> buffer_l_;
16
17    void loop{
18       //BUFFER LOGIC
19​
20       //loop buffer if buffer is not empty
21       //    if connected
22       //        POST buffer data and pop from buffer
23       //    else break
24            while (!buffer_msg_ids.empty()){
25                if (WiFi.status() == WL_CONNECTED){
26                       //create CAP MSG from raw data in buffers
27                        if (sendPostRequest(xmlchar_buf, msg_id_buf)){
28                            popBuffers();
29                        }
30                }
31        }
32    
33        //MAIN LOGIC
34    
35            //calculate readings and create CAP MSG
36            if (WiFi.status() != WL_CONNECTED)
37            {
38                bool connected = connect_to_wifi();
39                if (connected){
40                        //send MSG to server
41                        if (!sendPostRequest(xmlchar, msg)){
42                            //buffer MSG
43                            pushToBuffers();
44                        }
45                }
46                else{
47                        //buffer MSG
48                        pushToBuffers();
49                }
50            }
51            else{
52                //send MSG to server
53                if (!sendPostRequest(xmlchar, msg)){
54                        //buffer MSG
55                        pushToBuffers();
56                }
57            }
58    }
59​
60    void pushToBuffers(){
61            //push all the raw data needed for MSG to queues
62    }
63​
64    void popBuffers(){
65            //pop the front element from the queues
66    }

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1void beginOLED(){
2            //initial setup and starting of OLED Display
3    }
4    void displayText(){
5            //display the content in the OLED display
6            //in various places, this function is called to print sensor and other information
7    }
8    void getTimeStamp(){
9            //get the current time
10    }
11    void popBuffers(){
12            //pop the front element from the queues
13    }
14    void pushToBuffers(){
15        //push all the raw data needed for MSG to queues
16    }
17​
18    void setup(){
19            beginOLED();
20            wait_and_connect_to_wifi();
21            begin_sensors();
22            configTime();
23    }
24​
25    void loop(){
26    
27        //BUFFER LOGIC
28​
29        //loop buffer if buffer is not empty
30        //    if connected
31        //        POST buffer data and pop from buffer
32        //    else break
33            while (!buffer_msg_ids.empty()){
34                if (WiFi.status() == WL_CONNECTED){
35                        //generate CAP XML message from the data in buffers
36                        generateXMLStr();
37                        if (sendPostRequest(xmlchar_buf, msg_id_buf)){
38                            popBuffers();
39                        }
40                 }
41         }
42    
43            //MAIN LOGIC
44    
45            //calculate readings and create CAP MSG
46            int x = 0;
47            int rounds = 15;
48            int round_time = 2000;
49            while (x < rounds){
50                readTemperature();
51                readHumidity();
52                readPressure();
53                readLightIntensity();
54            
55                delay(round_time);
56                x++;
57            }
58            temperature = calculate_mean(t_, rounds);
59            humidity = calculate_mean(h_, rounds);
60            pressure = calculate_mean(p_, rounds);
61            light = calculate_mean(l_, rounds);
62    
63            temperature_sd = calculate_sd(t_, rounds, temperature);
64            humidity_sd = calculate_sd(h_, rounds, humidity);
65            pressure_sd = calculate_sd(p_, rounds, pressure);
66            light_sd = calculate_sd(l_, rounds, light);
67    
68            getTimeStamp(datetime_);
69    
70            //send WARNING e-mail
71            if ((temperature > 40) && (WiFi.status() == WL_CONNECTED)){
72                //if a warning e-mail has not sent in last 5minutes
73                //  send mail
74            }
75    
76            //generate CAP XML message from the calculated data
77            generateXMLStr();
78    
79            if (WiFi.status() != WL_CONNECTED)
80        {
81                bool connected = connect_to_wifi();
82                if (connected){
83                        //send MSG to server
84                        if (!sendPostRequest(xmlchar, msg)){
85                            //buffer MSG
86                            pushToBuffers();
87                        }
88                }
89                else{
90                        //buffer MSG
91                        pushToBuffers();
92                }
93            }
94            else{
95                //send MSG to server
96                if (!sendPostRequest(xmlchar, msg)){
97                        //buffer MSG
98                        pushToBuffers();
99                }
100            }
101    }

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1#database table model
2    class EMonitor(db.Model):
3            __tablename__ = 'sensor_data'
4            id = db.Column(db.Integer, primary_key=True)
5            msg_id = db.Column(db.String(128))
6            timestamp = db.Column(db.String(128))
7​
8            temperature = db.Column(db.Float)
9            humidity = db.Column(db.Float)
10            pressure = db.Column(db.Float)
11            light = db.Column(db.Float)
12​
13            temperature_sd = db.Column(db.Float)
14            humidity_sd = db.Column(db.Float)
15            pressure_sd = db.Column(db.Float)
16            light_sd = db.Column(db.Float)
17    
18    
19    def extract_data_from_xml(xml_str):
20            """
21            Given a XML string(CAP) this extracts the 'parameter' values
22            :param xml_str: XML as a string
23            :return: data as dictionary {name:value}
24            """
25  
26    def put_to_db(xml_data):
27            """
28            given a data dictionary this method put the data to the database
29            :param xml_data: data as dictionary {name:value}
30            :return: True if database write successful, otherwise False
31            """
32    
33    @app.route('/data', methods=['POST'])
34    def post():
35            xml_str = request.data
36            xml_data = extract_data_from_xml(xml_str)
37            print("[POST] /data : ", xml_data)
38            if put_to_db(xml_data):
39                return "DATABASE updated"
40            else:
41                return "DATABASE modification failed !"
42 
43    @app.route('/')
44    def index():
45            #query the database table and get the list of data
46            table = EMonitor.query.order_by(desc(EMonitor.timestamp)).limit(20).all()
47​
48            return render_template("index.html", table)