const int trig = 8; //define Arduino pin
const int echo = 7;
const int TX = 1;
const int RX = 0;
const int delay_time = 1000; //delay 1000 ms for every measurment
SoftwareSerial BT(0, 1);
//set Bluetooth RX (-> pin TX of Bluetooth Module), TX (-> pin RX of Bluetooth Module)
void setup() {
Serial.begin(9600); //set baud rate of Serial Monitor
BT.begin(9600); //set baud rate of Bluetooth
pinMode(trig, OUTPUT); //set trigger pin to OUTPUT (-> pin trig of Ultrasonic Sensor)
pinMode(echo, INPUT); //set echo pin to INPUT (-> pin echo of Ultrasonic Sensor)
Serial.println("Start!!!");
}
void loop() {
float duration; //duration to record the time of every back and forth
float distance;
digitalWrite(trig, HIGH); //trigger sona for 1 ms
delayMicroseconds(1000);
digitalWrite(trig, LOW);
duration = pulseIn(echo, HIGH);
//use pulseIn() function to get the time of pin echo from HIGH to LOW, unit=microseconds
distance = (duration / 2) * 0.034;
//distance = ( half of time of back and forth )x( wave velocity(use 0.034 cm per microsecond) )
Serial.print("Distance ="); //show result on Serial Monitor
Serial.print(distance);
Serial.println("cm");
delay(500);
int sendData = (int) (distance * 100); //times 100 and convert disance to integer
byte packet[3];
packet[0] = 97; //key send to phone
packet[1] = sendData / 256; //divides sendData to two 1 byte packets
packet[2] = sendData % 256;
if(BT.available() > 0) //check BT is succeed
if(BT.read() == 97) //check recieve key from phone
{
Serial.println("succeed!");
for(int i = 0; i < 3; i++)
BT.write(packet); //send packet to phone
}
