How to receive multiple data from Arduino via bluetooth to Android app?

Using Arduino Project Guidance
#1

So my project is about parking guidance system where I am required to tell user whether or not parking slots on a parking space is available. For my project I have 15 spaces I have no idea on how to fix my Arduino code, I already have my app finished but I don’t know how to fix my coding, can anyone please help guide me through this? Much thanks

edit: I am using MIT App Inventor

#include<SoftwareSerial.h>
#define TxD 18
#define RxD 19
SoftwareSerial bluetoothSerial(TxD, RxD);

//include the library code
#include<LiquidCrystal.h>
//initialize library with the numbers of the interface pins
LiquidCrystal lcd(38,36,34,32,30,28);

//pins used for Light Dependent Resistor (ldr)
const int ldrPin[] = {A0,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14};
//pins used for Light Emitting Diode (LED)
const int ledPin[] = {2,3,4,5,6,7,8,9,10,11,12,13,22,24,26};

int ldrStatus[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14}; //used to store readings from LDR

void setup() {

  Serial.begin(9600);
  bluetoothSerial.begin(9600)
  lcd.begin(16,2); //set up LCD's number of rows and columns
  lcd.print("Available Parking =" );

  //declare LED as output
  for(int n=0; n<15 ; n++)
  {
    pinMode(ledPin[n],OUTPUT); 
  }
}

void loop() {

  int slot[14];
  
  for (byte n = 0; n<15 ; n++) {
  ldrStatus[n] = analogRead(ldrPin[n]);
  ldrStatus[n] = analogRead(ldrPin[n]);

    //Availability of parking slots
    if (ldrStatus[n] >=200) {
    digitalWrite(ledPin[n], HIGH); //turn LED on
    slot[n] = 1; }
    else {
    digitalWrite(ledPin[n], LOW);            
    slot[n] = 0;}
  }
  
    int ParkingAvailable = 0;
    for (int i = 0; i <15 ; i++){
        ParkingAvailable = ParkingAvailable + slot[i];
    }
    
    lcd.setCursor(0,1);
    lcd.print(ParkingAvailable);
    
 Serial.println(ParkingAvailable);
 delay(1000);
 
 }
#2

Fifteen sensors and fourteen slots.
That could end badly.

#3

Using serial IO pins for LEDs.
That could end badly too.

#4

AWOL:
Using serial IO pins for LEDs.
That could end badly too.

Can you please help enlighten me? This is my very first time using Arduino, I thought the serial IO is pins 0,1 and 14-21? And whoops this was my old coding, for LDR I used analog inputs. I am so sorry I am just using whatever I have from my very basic knowledge.

#5

Oops, sorry. Scrub that second one - I was reading ldrStatus as using the serial pins (though I can't see why you're initialising the elements of ldrStatus)

First comment still stands though

#6

So, what's your problem, really?

Code seems to be OK other than that slot issue, and I'm wondering how the text on your LCD looks like as it's not going to fit on a single line.

#7

wvmarle:
So, what’s your problem, really?

Code seems to be OK other than that slot issue, and I’m wondering how the text on your LCD looks like as it’s not going to fit on a single line.

Sorry for not explaining in detail, it’s just that in my app I have 15 parking slots, each equipped with LDR, when there is a car present on it, the status on the app will change from available to not available. The thing is I have no idea how to code for the app.

    //Availability of parking slots
    if (ldrStatus[n] >=200) {
    digitalWrite(ledPin[n], HIGH); //turn LED on
    
    Serial.print("Slot ");
    Serial.print(slot[n]);
    Serial.println(" available");

    slot[n] = 1;
    
    else {
    digitalWrite(ledPin[n], LOW);

    Serial.print("Slot ");
    Serial.print(slot[n]);
    Serial.println(" unavailable");
            
    slot[n] = 0;}
  }

I added serial print here, is this acceptable? Just asking for opinions since I have no idea what I am doing but I am just trying what I can from what I know

And sorry since I used analog port 0 - 14 is that not 15 slots?

#8

sscloudstrifey:
The thing is I have no idea how to code for the app.

You mean you're having a problem communicating between the Arduino and the app?
Two options: run a server on the Arduino (if you have very few users), or use an external server and have Arduino send the data to that server, e.g. through a simple GET such as https://example.com/freeSpaces?number=5 while the app could do a similar request to your Arduino which would then have to run the web server itself.

[/quote]
And sorry since I used analog port 0 - 14 is that not 15 slots?
[/quote]

It is. Then why are you declaring an array to hold 14 slots?

#9