CODEWITHSUNDEEP
bluetooth-lowenergy
Mahmoud Mousa
Mahmoud Mousa

Reputation: 141

BLUNO Distance Monitoring Project

I'm trying to do a project where BLUNO (Arduino UNO + BLE) will connect to an iBeacon and make use of the RSSI detected.

I've already made contact between the BLUNO and the iBeacon through the AT commands. I can get RSSI result in the Arduino IDE serial monitor when I ping it with AT commands. My problem now is in sending those AT commands through an Arduino sketch. I know I've to use Serial Communication, but my Serial.Available function never returns more than 0.

void setup() {
  pinMode(13, OUTPUT);
  Serial.begin(115200);
  Serial.print("+++\r\n");
  Serial.print("AT+RSSI=?\r\n");
 }
void loop(){
  if(Serial.available()){
  digitalWrite(13, HIGH);
  delay(5000);
  }
}

What is irritating me is that I can connect BLUNO to my iPhone and get the RSSI on the serial monitor through AT commands. But that above code doesn't work! Any help?

Upvotes: 0

Views: 2017

Answers (1)

Mahmoud Mousa
Mahmoud Mousa

Reputation: 141

I'm almost done with the whole project for now.

my mistake in the last code was the initiation part that has to be done before the AT commands. The right way is 

 Serial.begin(115200);    //Initiate the Serial comm
  Serial.print("+"); 
  Serial.print("+"); 
  Serial.print("+");   // Enter the AT mode
  delay(500); // Slow down and wait for connection establishment

instead of 

 Serial.print("+++\r\n");

so yeah the rest is kind of alright. Keep in mind that this BLE thing REALLY sucks in terms of accuracy in locating a beacon. The RSSI reading keep fluctuating and the calculated distance using the simplified equation here somewhere on Stack overflow is REALLY unreliable.

So yeah keep that in mind yo!

Here's my full code just for reference. 

// while the AT connection is active, the serial port between the pc and the arduino is occuipied.
// You can manipluate the data on arduino, but to display on the serial monitor you need to exit the AT mode
char Data[100];
char RAW[3];
int INDEX;
char Value = '-';
void setup() {
  pinMode(13, OUTPUT); // This the onboard LED
  pinMode(8, OUTPUT); // This is connected to the buzzer
  Serial.begin(115200);    //Initiate the Serial comm
  Serial.print("+"); 
  Serial.print("+"); 
  Serial.print("+");   // Enter the AT mode
  delay(500); // Slow down and wait for connectin establishment
 }


void loop(){
    Serial.println("AT+RSSI=?"); // Ask about the RSSI
 for(int x=0 ; Serial.available() > 0 ; x++ ){    // get the Enter AT mode words
    //delay(20); // Slow down for accuracy
    Data[x] = Serial.read(); // Read and store Data Byte by Byte
    if (Data[x] == Value ) // Look for the elemnt of the array that have "-" that's the start of the RSSI value
      {
        INDEX=x;
      }
  }
    //Serial.println("AT+EXIT");    
    RAW[0] = Data[INDEX]; // Copy the RSSI value to RAW Char array
    RAW[1] = Data[INDEX+1]; 
    RAW[2] = Data[INDEX+2]; 
    RAW[3] = Data[INDEX+3];
    int RSSI = atoi(RAW);  //Convert the Array to an integer
    //Serial.println(RSSI);
    //delay(200); // Give the program time to process. Serial Comm sucks
    double D = exp(((RSSI+60)/-10)); //Calculate the distance but this is VERY inaccurate
    //Serial.println(D);
    if (D>1.00) // If the device gets far, excute the following>>
    {
      digitalWrite(13, HIGH);
      digitalWrite(8, HIGH);
      delay(500);
      digitalWrite(13, LOW);
      digitalWrite(8, LOW);
      delay(500);
    }

}

Upvotes: 3

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