Monday, September 5, 2016

Combining Arduino, Android, and the Cloud Part 3

In this 3 part series we look at how to create an Android app to monitor and control multiple WiFi enabled Arduinos using the cloud. In part 3 the finale we will look at how to send control data to the cloud using an Android App to control the Arduino WiFi nodes. To download the Android App .aia file to load into MIT App Inventor II use the following link: https://dl.dropboxusercontent.com/u/26591541/CloudHomeAutoEx2.aia


//Arduino MKR1000 Code****************************************************
/*
 This sketch was created for a tutorial called Combining Arduino, Android, and the Cloud Part 3 
 That was presented on the ForceTronics YouTube Channel. This code is public domain for anybody to 
 use or modify at your own risk

 Note that this code was leveraged from the Arduino WiFi101 examples and from a Sparkfun example 
 on using their cloud service Phant
 */


#include <SPI.h>
#include <WiFi101.h>

char ssid[] = "YourNetwork"; //  your network SSID (name)
char pass[] = "YourPassword";    // your network password (use for WPA, or use as key for WEP)
int keyIndex = 0;            // your network key Index number (needed only for WEP)
bool pData = false;  //used to toggle between posting data and getting data

int status = WL_IDLE_STATUS;

//define some constant variables for pins and node number
const int LED_PIN = 6; // Thing's onboard, green LED
const int ANALOG_PIN = A0; // The only analog pin on the Thing
const int NODE_NUM = 2; //node identifier
const char parseKey[] = "stamp";

//define areas for phant cloud address and security keys
const char PhantHost[] = "data.sparkfun.com";
const char pPublicKey[] = "PublicKeyForPosting";
const char pPrivateKey[] = "PrivateKeyForPosting";
const char gPublicKey[] = "PublicKeyForGetting";
const char gPrivateKey[] = "PublicKeyForGetting";
//The following variables are from Phant library created by Sparkfun.
String _pub;
String _prv;
String _host;
String _params;
static const char HEADER_POST_URL1[] PROGMEM = "POST /input/";
static const char HEADER_POST_URL2[] PROGMEM = ".txt HTTP/1.1\n";
static const char HEADER_PHANT_PRV_KEY[] PROGMEM = "Phant-Private-Key: ";
static const char HEADER_CONNECTION_CLOSE[] PROGMEM = "Connection: close\n";
static const char HEADER_CONTENT_TYPE[] PROGMEM = "Content-Type: application/x-www-form-urlencoded\n";
static const char HEADER_CONTENT_LENGTH[] PROGMEM = "Content-Length: ";

//timing for posting to the phant cloud
const unsigned long postRate = 15000;
unsigned long lastPost = 0;

void setup() {
  pinMode(LED_PIN, OUTPUT); //setup LED pin
  digitalWrite(LED_PIN, LOW); //Turn off LED
  Serial.begin(9600);
  while (!Serial) { //Note the code will not cont unless you open serial monitor
    ; // wait for serial port to connect. Needed for native USB port only
  }

  // check for the presence of the shield:
  if (WiFi.status() == WL_NO_SHIELD) {
    Serial.println("WiFi shield not present");
    // don't continue:
    while (true);
  }

  // attempt to connect to Wifi network:
  while (status != WL_CONNECTED) {
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(ssid);
    // Connect to WPA/WPA2 network. Change this line if using open or WEP network:
    status = WiFi.begin(ssid, pass);

    // wait 10 seconds for connection:
    delay(10000);
  }
  Serial.println("Connected to wifi");
  printWifiStatus(); //Print info about the WiFi network that you are connected to
}

void loop() {
  //Delay for set time then post and get data from Phant cloud
  if (lastPost + postRate <= millis())
  {
    if(pData) {
      if (postToPhant()) lastPost = millis();
      else lastPost = millis(); //Even if we fail delay whole cycle before we try again   
    } 
    else {
      if (getFromPhant()) lastPost = millis();
      else lastPost = millis(); //Even if we fail delay whole cycle before we try again 
    }
  }
}

//function that handles posting and getting data from phant cloud
int getFromPhant()

 //Set phant data
 phant(PhantHost, gPublicKey, gPrivateKey);
  
  WiFiClient client; //Create client object to communicate with the phant server

  if (!client.connect(PhantHost, 80)) { //Attempt to connect to phant server using port 80
    // If we fail to connect, return 0.
    return 0;
  }

  //Get data from phant cloud
    client.print(phantGet()); 
    client.println();
    Serial.println("sent get request.....");
   int cTrack = 0; //variable that tracks count to spell stamp
   bool match = false; //tracks when we have a match with "stamp" and we can then get control data
   int pCount = 0; //variable used to track whe we have control data
   while(1) { //loop until we get data and server closes connection
    if (client.available()) { //if data is available from phant server
      char c = client.read(); //read a bite of data from server
      if(!match) { //if true than we have not found the word "stamp" so keep looking
        if(c == parseKey[cTrack]) //check if we have a character match with word "stamp"
        {
          if(cTrack == (sizeof(parseKey)-2)) match = true; //if true it means we found a match for "stamp" in data from phant cloud
          cTrack++; //iterate this count if a character match was found
        }
        else { //if true means no character match so reset count
          cTrack = 0;
        }
      }
      else { //if true it means we found a match to "stamp" and we are ready to get control data
        
        if(pCount == 3) { //if true we are at the point in the data to read control data for node oen
          Serial.print(c);
          int dControl = c - '0'; //convert char data to an int by subtract an ASCII zero
          if(dControl == 1 | dControl == 0) digitalWrite(LED_PIN, dControl); //make sure data is a one or zer and set LED pin with it
        }
        pCount++; //iterate the parse counter
      }
    }

    // if the server's disconnected, stop the client:
    if (!client.connected()) {
      Serial.println();
      Serial.println("disconnecting.");
      client.stop(); //stop client, if you don't have this you will create too many clients and server won't let you connect anymore
      break; //This is how we get out of the loop
    }
   }
  pData = true; //set to true so we post data to cloud next loop
  return 1; // Return success
}

//function used to post data to phant cloud
int postToPhant()
{
  // Declare an object from the Phant library - phant
  phant(PhantHost, pPublicKey, pPrivateKey);
  //These calls build the web communication strings with Phant
  phantAdd("adcdata", analogRead(ANALOG_PIN)); //specify field and data used in that field
  phantAdd("wifinode", NODE_NUM);
  
  WiFiClient client; //Create client object to communicate with the phant server

  if (!client.connect(PhantHost, 80)) { //Attempt to connect to phant server using port 80
    // If we fail to connect, return 0.
    pData = false; //set to false so we get data from cloud next loop
    return 0;
  }

  //Send post to phant server
  client.print(phantPost()); 
  
  // if there are incoming bytes available
  // from the server, read them and print them:
  while (client.available()) {
    String line = client.readStringUntil('\r');
    //Do something with data
  }
  client.stop();
  pData = false; //set to false so we get data from cloud next loop
  return 1; // Return success
}

void printWifiStatus() {
  // print the SSID of the network you're attached to:
  Serial.print("SSID: ");
  Serial.println(WiFi.SSID());

  // print your WiFi shield's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print("IP Address: ");
  Serial.println(ip);

  // print the received signal strength:
  long rssi = WiFi.RSSI();
  Serial.print("signal strength (RSSI):");
  Serial.print(rssi);
  Serial.println(" dBm");
  Serial.println();
}


//This is from phant library, initializes variables
void phant(String host, String publicKey, String privateKey) {
  _host = host;
  _pub = publicKey;
  _prv = privateKey;
  _params = "";
}

//From phant library, builds string of field and data
void phantAdd(String field, int data) {

  _params += "&" + field + "=" + String(data);

}

//From phant library, builds string to get data from Phant cloud
String phantGet() {
  String result = "GET /output/" + _pub + ".csv?page=1 HTTP/1.1\n";
  result += "Host: " + _host + "\n";
  result += "Connection: close\n";

  return result;

}

//From phant library, builds the string used to post data to phant over web services
String phantPost() {

  String params = _params.substring(1);
  String result;
  //String result = "POST /input/" + _pub + ".txt HTTP/1.1\n";
  for (int i=0; i<strlen(HEADER_POST_URL1); i++)
  {
    result += (char)pgm_read_byte_near(HEADER_POST_URL1 + i);
  }
  result += _pub;
  for (int i=0; i<strlen(HEADER_POST_URL2); i++)
  {
    result += (char)pgm_read_byte_near(HEADER_POST_URL2 + i);
  }
  result += "Host: " + _host + "\n";
  //result += "Phant-Private-Key: " + _prv + "\n";
  for (int i=0; i<strlen(HEADER_PHANT_PRV_KEY); i++)
  {
    result += (char)pgm_read_byte_near(HEADER_PHANT_PRV_KEY + i);
  }
  result += _prv + '\n';
  //result += "Connection: close\n";
  for (int i=0; i<strlen(HEADER_CONNECTION_CLOSE); i++)
  {
    result += (char)pgm_read_byte_near(HEADER_CONNECTION_CLOSE + i);
  }
  //result += "Content-Type: application/x-www-form-urlencoded\n";
  for (int i=0; i<strlen(HEADER_CONTENT_TYPE); i++)
  {
    result += (char)pgm_read_byte_near(HEADER_CONTENT_TYPE + i);
  }  
  //result += "Content-Length: " + String(params.length()) + "\n\n";
  for (int i=0; i<strlen(HEADER_CONTENT_LENGTH); i++)
  {
    result += (char)pgm_read_byte_near(HEADER_CONTENT_LENGTH + i);
  } 
  result += String(params.length()) + "\n\n";
  result += params;

  _params = "";
  return result;
}

//This function convers the ADC level integer value into float voltage value.
//The inputs are the measured ADC value and the ADC reference voltage level
//The formula used was obtained from the data sheet: (ADC value / 1024) x ref voltage
float convertToVolt(float refVal, int aVAL) {
  return (((float)aVAL/1024)*refVal);
}

//this function calculates temp in F from TMP36 temp sensor
//see TMP36 datasheet to understand algorithm used
float calculateTempF(float v1) { 
 float temp = 0;
 //calculate temp in C, .75 volts is 25 C. 10mV per degree
 if (v1 < .75) { temp = 25 - ((.75-v1)/.01); } //if below 25 C
 else if (v1 == .75) {temp = 25; }
 else { temp = 25 + ((v1 -.75)/.01); } //if above 25
 //convert to F
 temp =((temp*9)/5) + 32;
 return temp;
}

//Arduino ESP8266 Code****************************************************
/*
 This sketch was created for a tutorial called Combining Arduino, Android, and the Cloud Part 3 
 That was presented on the ForceTronics YouTube Channel. This code is public domain for anybody to 
 use or modify at your own risk

 Note that this code was leveraged from a Sparkfun example 
 on using their cloud service Phant
 */

// Include the ESP8266 WiFi library. (Works a lot like the
// Arduino WiFi library.)
#include <ESP8266WiFi.h>
// Include the SparkFun Phant library.
#include <Phant.h>

//Set your network name and password
const char WiFiSSID[] = "YourNetwork";
const char WiFiPSK[] = "YourPassword";

//define constants for pin control and node number
const int LED_PIN = 5; // Thing's onboard, green LED
const int ANALOG_PIN = A0; // The only analog pin on the Thing
const int NODE_NUM = 1; //node identifier
const char parseKey[] = "stamp";
bool pData = false;  //used to toggle between posting data and getting data

//declare phant address and security keys
const char PhantHost[] = "data.sparkfun.com";
const char pPublicKey[] = "PublicKeyForPosting";
const char pPrivateKey[] = "PrivateKeyForPosting";
const char gPublicKey[] = "PublicKeyForGetting";
const char gPrivateKey[] = "PublicKeyForGetting";

//specify the rate that you post data to cloud
const unsigned long postRate = 15000;
unsigned long lastPost = 0;

void setup() 
{
  initHardware(); //setup arduino hardware
  connectWiFi(); //Connect your WiFi network
  digitalWrite(LED_PIN, HIGH);
}

void loop() 
{ //loop until it is time to post data to phant cloud
  if (lastPost + postRate <= millis())
  {
    if(pData) {
      if (postToPhant()) lastPost = millis();
      else lastPost = millis(); //Even if we fail delay whole cycle before we try again   
    } 
    else {
      if (getFromPhant()) lastPost = millis();
      else lastPost = millis(); //Even if we fail delay whole cycle before we try again 
    }
  }
}

//function used to connect to WiFi network
void connectWiFi()
{
  byte ledStatus = LOW;
  // Set WiFi mode to station (as opposed to AP or AP_STA)
  WiFi.mode(WIFI_STA);
  // WiFI.begin([ssid], [passkey]) initiates a WiFI connection
  // to the stated [ssid], using the [passkey] as a WPA, WPA2,
  // or WEP passphrase.
  WiFi.begin(WiFiSSID, WiFiPSK);
  
  // Use the WiFi.status() function to check if the ESP8266
  // is connected to a WiFi network.
  while (WiFi.status() != WL_CONNECTED)
  {
    // Blink the LED
    digitalWrite(LED_PIN, ledStatus); // Write LED high/low
    ledStatus = (ledStatus == HIGH) ? LOW : HIGH;
    
    // Delays allow the ESP8266 to perform critical tasks
    // defined outside of the sketch. These tasks include
    // setting up, and maintaining, a WiFi connection.
    delay(100);
    // Potentially infinite loops are generally dangerous.
    // Add delays -- allowing the processor to perform other
    // tasks -- wherever possible.
  }
}

//function that sets up some initial hardware states
void initHardware()
{
  Serial.begin(9600);
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);
}

//function that handles posting and getting data from phant cloud
int getFromPhant()

 //Set phant data
 Phant phant(PhantHost, gPublicKey, gPrivateKey);
  
  WiFiClient client; //Create client object to communicate with the phant server

  if (!client.connect(PhantHost, 80)) { //Attempt to connect to phant server using port 80
    // If we fail to connect, return 0.
    return 0;
  }

  //Get data from phant cloud
    client.print(phant.get()); 
    client.println();
   int cTrack = 0; //variable that tracks count to spell stamp
   bool match = false; //tracks when we have a match with "stamp" and we can then get control data
   int pCount = 0; //variable used to track whe we have control data
   while(1) { //loop until we get data and server closes connection
    if (client.available()) { //if data is available from phant server
      char c = client.read(); //read a bite of data from server
      if(!match) { //if true than we have not found the word "stamp" so keep looking
        if(c == parseKey[cTrack]) //check if we have a character match with word "stamp"
        {
          if(cTrack == (sizeof(parseKey)-2)) match = true; //if true it means we found a match for "stamp" in data from phant cloud
          cTrack++; //iterate this count if a character match was found
        }
        else { //if true means no character match so reset count
          cTrack = 0;
        }
      }
      else { //if true it means we found a match to "stamp" and we are ready to get control data
        
        if(pCount == 1) { //if true we are at the point in the data to read control data for node oen
          int dControl = c - '0'; //convert char data to an int by subtract an ASCII zero
          if(dControl == 1 | dControl == 0) digitalWrite(LED_PIN, dControl); //make sure data is a one or zer and set LED pin with it
        }
        pCount++; //iterate the parse counter
      }
    }

    // if the server's disconnected, stop the client:
    if (!client.connected()) {
      client.stop(); //stop client, if you don't have this you will create too many clients and server won't let you connect anymore
      break; //This is how we get out of the loop
    }
   }
  pData = true; //set to true so we post data to cloud next loop
  return 1; // Return success
}

//this function takes data and posts it to the cloud
int postToPhant()

  // Declare an object from the Phant library - phant
  Phant phant(PhantHost, pPublicKey, pPrivateKey);
  //These functions build data and field string that will be sent to phant cloud
  phant.add("adcdata", analogRead(ANALOG_PIN));
  phant.add("wifinode", NODE_NUM);
  
  // Now connect to data.sparkfun.com, and post our data:
  WiFiClient client; //declare client object that will post the data
  const int httpPort = 80; //specify port to post through
  
  if (!client.connect(PhantHost, httpPort)) //attempt to connect to phant
  {
    // If we fail to connect, return 0.
    return 0;
  }
 //Send post to phant
  client.print(phant.post());
  
  // Read all the lines of the reply from server and print them to Serial
  while(client.available()){
    String line = client.readStringUntil('\r');
    //Serial.print(line); // Trying to avoid using serial
  }
  pData = false; //set to false so we get data from cloud next loop
  return 1; // Return success
}