How to make contactless doorbell with Arduino

Well in this post I want share with you how you can make a contactless doorbell. It is very simple, you just need few things.

• One loud speaker
• One Serial MP3 player for Arduino
• One Ultrasonic Sensor
• One Green LED
• One 10k ohm resistor
• One micro SD card (this is where your doorbell sound track will go make sure you name the sound track 001)
• Few jumper wires
• And a Arduino board

After connecting everything as shown in the diagram above upload the sketch below, and that's all.

#include <SoftwareSerial.h> #define ARDUINO_RX 5 //should connect to TX of the Serial MP3 Player module #define ARDUINO_TX 6 //connect to RX of the module SoftwareSerial mySerial(ARDUINO_RX, ARDUINO_TX); static int8_t Send_buf[8] = {0} ; #define CMD_SEL_DEV 0X09 #define DEV_TF 0X02 #define CMD_PLAY_W_VOL 0X22 int led = 4; int trigPin1 = 8; int echoPin1 = 9; void setup() {   pinMode(led, OUTPUT);   pinMode(trigPin1, OUTPUT);   pinMode(echoPin1, INPUT);       mySerial.begin(9600);         Serial.begin(9600);       delay(500);//Wait chip initialization is complete         sendCommand(CMD_SEL_DEV, DEV_TF);//select the TF card       delay(200);//wait for 200ms } void loop() { delay(500); Serial.println("\n");  int duration1, distance1;   digitalWrite (trigPin1, HIGH);   delayMicroseconds (10);   digitalWrite (trigPin1, LOW);   duration1 = pulseIn (echoPin1, HIGH);   distance1 = (duration1/2) / 29.1;       Serial.print("1st Sensor: ");       Serial.print(distance1);       Serial.print("cm  ");   if (distance1 < 30) {  // Change the number for long or short distances.  digitalWrite(led, LOW);  sendCommand(CMD_PLAY_W_VOL, 0X1E001);//Play the sound track    delay(5000);   } else {     digitalWrite(led, HIGH);   }  } void sendCommand(int8_t command, int16_t dat) {   delay(20);   Send_buf[0] = 0x7e; //starting byte   Send_buf[1] = 0xff; //version   Send_buf[2] = 0x06; //the number of bytes of the command without starting byte and ending byte   Send_buf[3] = command; //   Send_buf[4] = 0x00;//0x00 = no feedback, 0x01 = feedback   Send_buf[5] = (int8_t)(dat >> 8);//datah   Send_buf[6] = (int8_t)(dat); //datal   Send_buf[7] = 0xef; //ending byte   for(uint8_t i=0; i<8; i++)//   {     mySerial.write(Send_buf[i]) ;   } }