initial commit

build

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+#!/bin/bash
+g++ thingSpeak.cpp network/SocketClient.cpp -o thingSpeak

example_crontab/crontab-backup

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+# Edit this file to introduce tasks to be run by cron.
+# 
+# Each task to run has to be defined through a single line
+# indicating with different fields when the task will be run
+# and what command to run for the task
+# 
+# To define the time you can provide concrete values for
+# minute (m), hour (h), day of month (dom), month (mon),
+# and day of week (dow) or use '*' in these fields (for 'any').# 
+# Notice that tasks will be started based on the cron's system
+# daemon's notion of time and timezones.
+# 
+# Output of the crontab jobs (including errors) is sent through
+# email to the user the crontab file belongs to (unless redirected).
+# 
+# For example, you can run a backup of all your user accounts
+# at 5 a.m every week with:
+# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
+# 
+# For more information see the manual pages of crontab(5) and cron(8)
+# 
+# m h  dom mon dow   command
+*/30  *   *   *   *    ~/exploringBB/chp11/thingSpeak/thingSpeak > /dev/null 2>&1

network/SocketClient.cpp

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+#include "SocketClient.h"
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+using namespace std;
+
+namespace exploringBB {
+
+SocketClient::SocketClient(std::string serverName, int portNumber) {
+   this->socketfd = -1;
+   this->server = NULL;
+   this->serverName = serverName;
+   this->portNumber = portNumber;
+   this->isConnected = false;
+}
+
+int SocketClient::connectToServer(){
+    socketfd = socket(AF_INET, SOCK_STREAM, 0);
+    if (socketfd < 0){
+    	perror("Socket Client: error opening socket.\n");
+    	return 1;
+    }
+    server = gethostbyname(serverName.data());
+    if (server == NULL) {
+        perror("Socket Client: error - no such host.\n");
+        return 1;
+    }
+    bzero((char *) &serverAddress, sizeof(serverAddress));
+    serverAddress.sin_family = AF_INET;
+    bcopy((char *)server->h_addr,(char *)&serverAddress.sin_addr.s_addr, server->h_length);
+    serverAddress.sin_port = htons(portNumber);
+
+    if (connect(socketfd, (struct sockaddr *) &serverAddress, sizeof(serverAddress)) < 0){
+    	perror("Socket Client: error connecting to the server.\n");
+    	return 1;
+    }
+    this->isConnected = true;
+    return 0;
+}
+
+int SocketClient::send(std::string message){
+   const char *writeBuffer = message.data();
+   int length = message.length();
+   int n = write(this->socketfd, writeBuffer, length);
+   if (n < 0){
+      perror("Socket Client: error writing to socket");
+      return 1;
+   }
+   return 0;
+}
+
+string SocketClient::receive(int size=1024){
+    char readBuffer[size];
+    int n = read(this->socketfd, readBuffer, sizeof(readBuffer));
+    if (n < 0){
+       perror("Socket Client: error reading from socket");
+    }
+    return string(readBuffer);
+}
+
+int SocketClient::disconnectFromServer(){
+   this->isConnected = false;
+   close(this->socketfd);
+   return 0;
+}
+
+SocketClient::~SocketClient() {
+   if (this->isConnected == true){
+      disconnectFromServer();
+   }
+}
+}

network/SocketClient.h

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+#ifndef SOCKETCLIENT_H_
+#define SOCKETCLIENT_H_
+
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <string>
+
+namespace exploringBB {
+
+class SocketClient {
+
+private:
+    int         socketfd;
+    struct      sockaddr_in   serverAddress;
+    struct      hostent       *server;
+    std::string serverName;
+    int         portNumber;
+    bool        isConnected;
+
+public:
+   SocketClient(std::string serverName, int portNumber);
+   virtual int connectToServer();
+   virtual int disconnectFromServer();
+   virtual int send(std::string message);
+   virtual std::string receive(int size);
+   bool isClientConnected() { return this->isConnected; }
+   virtual ~SocketClient();
+};
+
+}
+#endif /* SOCKETCLIENT_H_ */

thingSpeak.cpp

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+#include <iostream>
+#include <sstream>
+#include <fstream>
+#include "network/SocketClient.h"
+#define ADC_PATH "/sys/bus/iio/devices/iio:device0/in_voltage"
+#define ADC 0
+using namespace std;
+using namespace exploringBB;
+
+float getTemperature(int adc_value) {     // from the TMP36 datasheet
+   float cur_voltage = adc_value * (1.80f/4096.0f); // Vcc = 1.8V, 12-bit
+   float diff_degreesC = (cur_voltage-0.75f)/0.01f;
+   return (25.0f + diff_degreesC);
+}
+
+int readAnalog(int number){
+   stringstream ss;
+   ss << ADC_PATH << number << "_raw";
+   fstream fs;
+   fs.open(ss.str().c_str(), fstream::in);
+   fs >> number;
+   fs.close();
+   return number;
+}
+
+int main() {
+   ostringstream head, data;
+   cout << "Starting ThingSpeak Example" << endl;
+   SocketClient sc("api.thingspeak.com",80);
+   data << "field1=" << getTemperature(readAnalog(ADC)) << endl;
+   cout << "Sending the temperature: " <<  getTemperature(readAnalog(ADC)) << endl;
+   sc.connectToServer();
+   head << "POST /update HTTP/1.1\n"
+        << "Host: api.thingspeak.com\n"
+        << "Connection: close\n"
+        << "X-THINGSPEAKAPIKEY: Z7PNWRYKDEBRX5F7\n"
+        << "Content-Type: application/x-www-form-urlencoded\n"
+        << "Content-Length:" << string(data.str()).length() << "\n\n";
+   sc.send(string(head.str()));
+   sc.send(string(data.str()));
+   string rec = sc.receive(1024);
+   cout << "[" << rec << "]" << endl;
+   cout << "End of ThingSpeak Example" << endl;
+}