Technomate

// program for two LEDs on at a time and two LEDs off at same time //BY-ALOK KUMAR PANDEY //.................................................................................// int led1=13, led2=12, led3=11,led4 = 10; void setup() {   pinMode(led1, OUTPUT);         // here pin 13(i.e. led1) set as output pin   pinMode(led2, OUTPUT);         // here pin 12(i.e. led2) set as output pin   pinMode(led3, OUTPUT);         // here pin 11(i.e. led3) set as output pin   pinMode(led4, OUTPUT);         // here pin 10(i.e. led4) set as output pin } void loop() {  digitalWrite(led1, HIGH);    digitalWrite(led2, HIGH);     digitalWrite(led3, LOW);   digitalWrite(led4, LOW);    delay(1000);    digitalWrite(led1, LOW);    digitalWrite(led2, LOW);     digitalWrite(led3, HIGH);   digitalWrite(led4, HIGH);   delay(1000);  }

//program for 4 LED blinking one by one //by-ALOK KUMAR PANDEY //..........................................................................................// int led1=13, led2 = 12, led3 = 11, led4 =10; // All pin are difined by variables void setup() {   pinMode(led1, OUTPUT);         // here pin 13(i.e. led1) set as output pin   pinMode(led2, OUTPUT);         // here pin 12(i.e. led2) set as output pin   pinMode(led3, OUTPUT);         // here pin 11(i.e. led3) set as output pin   pinMode(led4, OUTPUT);         // here pin 10(i.e. led4) set as output pin } void loop() {  digitalWrite(led1, HIGH);       // here we set led1 as high(i.e. pin no. 13) it means led1 get on.  delay(1000);                    //delay of one second  digitalWrite(led1,LOW);        // here we set led1 as low(i.e. pin no. 13) it means led1 get off.  digitalWrite(led2, HIGH);      // here we set led2 as high(i.e. pin no. 12) it means led1 get on.  delay(1000);  

//program for TWO LED blinking one by one //by-ALOK KUMAR PANDEY //....................................................................................// int led1 =13, led2 =12; void setup() {   pinMode(led1, OUTPUT);         // here pin 13(i.e. led1) set as output pin   pinMode(led2, OUTPUT);         // here pin 12(i.e. led2) set as output pin } void loop()  {   digitalWrite(led1, HIGH);      // here we set led1 as low(i.e. pin no. 13) it means led1 get on.   digitalWrite(led2, LOW);       // here we set led2 as high(i.e. pin no. 12) it means led1 get off.   delay(1000);   digitalWrite(led1,LOW);        // here we set led1 as low(i.e. pin no. 13) it means led1 get off.   digitalWrite(led2, HIGH);      // here we set led2 as high(i.e. pin no. 12) it means led1 get on.   delay(1000);       }

//program for single LED blinking //by-ALOK KUMAR PANDEY //....................................................................................// int led = 13;                            //we difine pin number 13 as name led void setup()                            // this loop run sigle(one) time  {             pinMode(led,OUTPUT);        //here we difine pin no. 13 (i.e. led)as output pin } void loop() {                          //this loop run infinite times  digitalWrite(led, HIGH);      // here we set pin 13 (i.e. led) high, it means it get on  delay(1000);                        // one second delay  digitalWrite(led, LOW);     // here we set pin 13 (i.e. led) low, it means it get off  delay(1000);                     // again one second delay. }

Full form of sonar is Sound navigation and ranging. It is mostly used on ships for measuring the depth of water. This is accomplished by sending an acoustic pulse and measuring the time for the echo or return from the bottom. By knowing the speed of sound in the water, the depth is calculated by multiplying the speed by one-half of time traveled. Sonars are also used in the submarine to navigate and detect an object on or under the surface of the water.  History From millions of year some animals using this technique for communication and object detection of objects, like Dolphins and bats. The first time it is used by the human in 1490 by Leonardo da Vinci. A tube instated into the water was said to be used to detect vessel by placing an ear to the tube. The use of sound to echo location underwater in the same way as bats use sound for aerial navigation. The world’s first patent for an underwater echo ranging device was filed at the British patent office by English m