Initial commit

esp32_stm32_bridge_p.ino

+#include <WiFi.h>
+
+#define buttonPin 0 
+#define LEDPin 5
+
+// Network information
+char* ssid = "XXXXXXXXXXXX";
+const char* password = "XXXXXXXXXXXXX";
+
+// ThingSpeak Settings
+char server[] = "api.thingspeak.com";
+String writeAPIKey = "XXXXXXXXXXXXXXXXX";
+
+// Constants
+const unsigned long postingInterval = 15L * 1000L;
+
+// Global Variables
+unsigned long lastConnectionTime = 0;
+int measurementNumber = 0;
+
+// A 1 for each value in the telemetry String which should be send to the webserver
+int values_to_plot[] = {0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0};
+
+void setup(){
+  
+    Serial.begin(115200);
+    Serial.println("SETUP");
+    pinMode(buttonPin,INPUT);
+    pinMode(LEDPin, OUTPUT);
+    Serial.println("connectWiFi");
+    connectWiFi();
+    Serial.println("connectWiFi DONE");
+    
+}
+
+void loop(){
+  const int numberPoints = 7;
+  float wifiStrength;
+
+  // In each loop, make sure there is always an internet connection.
+    if (WiFi.status() != WL_CONNECTED) { 
+        connectWiFi();
+    }
+    String storedData = "";
+    if( Serial.available()){ // if new data is coming from the HW Serial
+      Serial.println("Serial.available");
+    int str_len = 0;
+       while(Serial.available())          // reading data into char array
+       {
+         delay(2);  // Delay to allow byte to arrive in input buffer
+         char inChar = Serial.read();
+         storedData += inChar;
+         //Serial1.println("Stored Char: ");
+         str_len++;
+       }
+    Serial.print("Stored Data: ");
+    Serial.println(storedData);
+    String prefix = storedData.substring(0, 5);
+    Serial.print("Prefix: ");
+    Serial.println(prefix);
+    if (prefix == "WiFi,"){
+      Serial.print("Got Data To Send");
+      unsigned char datToSend[str_len];
+      for (int i=0; i<str_len; i++){
+        datToSend[i+1] = (unsigned char) storedData[i];
+      }
+      // field1
+      String str_for_thingspeak = get_str_for_thingspeak(storedData);
+      Serial.println("Will send: " + str_for_thingspeak);
+      httpRequest(str_for_thingspeak);
+      delay(100);
+    }
+
+    }
+}
+
+void connectWiFi(){
+    WiFi.begin(ssid, password);
+    delay(400);
+    while (WiFi.status() != WL_CONNECTED){
+        delay(3000);
+        Serial.print(".");
+        Serial.print(WiFi.status());
+    }
+
+    // Show the user a connection is successful.
+    Serial.println("Connected");
+    blinkX(5,50);  
+}
+
+void httpRequest(String dataToSend) {
+
+    WiFiClient client;
+    
+    if (!client.connect(server, 80)){
+      
+        Serial.println("connection failed");
+        lastConnectionTime = millis();
+        client.stop();
+        return;     
+    }
+    
+    else{
+        
+        // create data string to send to ThingSpeak
+        String data = dataToSend;
+        //String data = "field1=" + String(field1Data) + "&field2=" + String(field2Data); //shows how to include additional field data in http post
+        
+        // POST data to ThingSpeak
+        if (client.connect(server, 80)) {
+          
+            client.println("POST /update HTTP/1.1");
+            client.println("Host: api.thingspeak.com");
+            client.println("Connection: close");
+            client.println("User-Agent: ESP32WiFi/1.1");
+            client.println("X-THINGSPEAKAPIKEY: "+writeAPIKey);
+            client.println("Content-Type: application/x-www-form-urlencoded");
+            client.print("Content-Length: ");
+            client.print(data.length());
+            client.print("\n\n");
+            client.print(data);
+            
+            //Serial.println("RSSI = " + String(field1Data));
+            lastConnectionTime = millis();   
+        }
+    }
+    client.stop();
+}
+
+// Take a number of measurements of the WiFi strength and return the average result.
+int getStrength(int points){
+    long rssi = 0;
+    long averageRSSI=0;
+    
+    for (int i=0;i < points;i++){
+        rssi += WiFi.RSSI();
+        delay(20);
+    }
+
+   averageRSSI=rssi/points;
+    return averageRSSI;
+}
+
+// Flash the LED a variable number of times with a variable delay.
+void blinkX(int numTimes, int delayTime){ 
+    for (int g=0;g < numTimes;g++){
+
+        // Turn the LED on and wait.
+        digitalWrite(LEDPin, HIGH);  
+        delay(delayTime);
+
+        // Turn the LED off and wait.
+        digitalWrite(LEDPin, LOW);
+        delay(delayTime);
+        
+    }
+}
+
+
+// Gets a telemetry string from the stm32 and creates a string for the thingspeak-api
+String get_str_for_thingspeak(String storedData){
+  String str_for_thingspeak = "";
+  int val_cnt = 1; // Counts the fields for the server
+  int prev_i = 0;
+  int val_ind = 0;
+  storedData = storedData + ",";
+  for (int i = 0; i < storedData.length(); i++) {
+  if (storedData.substring(i, i+1) == ",") {
+    String temp_value = storedData.substring(prev_i+1, i);
+    if ((val_ind>1) and (values_to_plot[val_ind]==1)){
+      str_for_thingspeak = str_for_thingspeak + "field" + (val_cnt) + "=" + temp_value + "&";
+      val_cnt++;
+    }
+    prev_i = i;    
+    val_ind++;
+  }
+}
+  return str_for_thingspeak.substring(0, str_for_thingspeak.length()-1); 
+}
+
+
+
+
+
+
+