Tips for Email writting

1) Always have a proper subject
                                      
                Give a clear and brief subject line that showcase about the letter/message
                Ex : Parents meeting in school

2) Use simple sentences
                 Don't make your letter so fishy that people find it difficult to read and understand what                        you  have written,like using long difficult words or complex sentences etc.

3) Address the letter in formal or informal way
                 Before you write the letter to whom you are representing it to is important.
                  a friend or principle etc

4) Be careful with the language
                 Use English language while writing do not mix up your mother tongue,
                  don't  use short forms (like sms) you ( u ) would (wd) etc

5) Give a positive response
                  Whatever you write in the letter let that focus on positive points.   

c programs to add two numbers using cmd line arguments

-Write the code in the editors like vc edit in fedora

-Example add.c

-Save the file.

#include<stdio.h>
#include<stdlib.h>
int main(int argc, char * argv[]) {
       int i, sum = 0;

       if (argc != 3) {
              printf("You have forgot to specify two numbers.");
              exit(1);
       }
     printf("The sum is : ");
    sum= atoi(argv[1])+atoi(argv[2]);
     printf("%d", sum);
    return 0;

}


-execute the file like

C:bin> cc add.c

C:bin> ./a.out 10 20


output : 30
 

C program to add numbers and execute using cmd line arguments

-Write the code in the editors like vc edit in fedora
-Example add.c

#include<stdio.h>
void main(int argc , char * argv[])  
{
  int i,sum=0; if(argc!=3)  
{
printf("enter two numbers numbers.");  
exit(1);
  }
  printf("The sum is : ");
  for(i=1;i<argc;i++)
sum = sum + atoi(argv[i]);
printf("%d",sum);  
}

-Save the file.
-execute the file like
C:bin> cc add.c
C:bin> ./a.out 10 20

output : 30

 

wireless transfer of data from arduino to server using esp8266 with example of DHT11

#include "SoftwareSerial.h"
String ssid ="yourSSID";
String password="yourPassword";
SoftwareSerial esp(6, 7);// RX, TX

String data;
String server = "yourServer"; 
String uri = "yourURI";

int DHpin = 8;
byte dat [5];
String temp ,hum;


void setup() {
pinMode (DHpin, OUTPUT);
esp.begin(9600);
Serial.begin(9600);
reset();
connectWifi();
}

//reset the esp8266 module
void reset() {
esp.println("AT+RST");
delay(1000);
if(esp.find("OK") ) Serial.println("Module Reset");
}

//connect to your wifi network
void connectWifi() {
String cmd = "AT+CWJAP=\"" +ssid+"\",\"" + password + "\"";
esp.println(cmd);
delay(4000);
if(esp.find("OK")) {
Serial.println("Connected!");
}
else {
connectWifi();
Serial.println("Cannot connect to wifi"); }
}

byte read_data () {
byte data;
for (int i = 0; i < 8; i ++) {
if (digitalRead (DHpin) == LOW) {
while (digitalRead (DHpin) == LOW); // wait for 50us
delayMicroseconds (30); // determine the duration of the high level to determine the data is '0 'or '1'
if (digitalRead (DHpin) == HIGH)
data |= (1 << (7-i)); // high front and low in the post
while (digitalRead (DHpin) == HIGH);
// data '1 ', wait for the next one receiver
}
} return data; }


void start_test () {
digitalWrite (DHpin, LOW); // bus down, send start signal
delay (30); // delay greater than 18ms, so DHT11 start signal can be detected
digitalWrite (DHpin, HIGH);
delayMicroseconds (40); // Wait for DHT11 response
pinMode (DHpin, INPUT);
while (digitalRead (DHpin) == HIGH);
delayMicroseconds (80);
// DHT11 response, pulled the bus 80us
if (digitalRead (DHpin) == LOW);
delayMicroseconds (80);
// DHT11 80us after the bus pulled to start sending data
for (int i = 0; i < 4; i ++)
// receive temperature and humidity data, the parity bit is not considered
dat[i] = read_data ();
pinMode (DHpin, OUTPUT);
digitalWrite (DHpin, HIGH);
// send data once after releasing the bus, wait for the host to open the next Start signal
}

void loop () {
start_test ();
// convert the bit data to string form
hum = String(dat[0]);
temp= String(dat[2]);
data = "temperature=" + temp + "&humidity=" + hum;// data sent must be under this form //name1=value1&name2=value2.
httppost();
delay(1000);
}

void httppost () {
esp.println("AT+CIPSTART=\"TCP\",\"" + server + "\",80");//start a TCP connection.
if( esp.find("OK")) {
Serial.println("TCP connection ready");
} delay(1000);
String postRequest =
"POST " + uri + " HTTP/1.0\r\n" +
"Host: " + server + "\r\n" +
"Accept: *" + "/" + "*\r\n" +
"Content-Length: " + data.length() + "\r\n" +
"\r\n" + data; String sendCmd = "AT+CIPSEND=";//determine the number of characters to be sent.
esp.print(sendCmd);
esp.println(postRequest.length() );
delay(500);
if(esp.find(">")) { Serial.println("Sending.."); esp.print(postRequest);
if( esp.find("SEND OK")) { Serial.println("Packet sent");
while (esp.available()) {
String tmpResp = esp.readString();
Serial.println(tmpResp);
}
// close the connection
esp.println("AT+CIPCLOSE");
}
}
}