how to send data serially and simultaneously read serial data using json library

Question

i just started using the ArduinoJson library for my project. my aim is to send three sensor values using BT to a RasPi from my arduino nano using json format. Also, control a relay by receiving '0' or '1' from BT.

I am successfully able to send data. But, when i include the following piece of code: (to read serial data) if (Serial.available > 0) { z = Serial.read(); ............... }

and i send a '1'; my data transmission is disturbed and the json string is affected. when i send '0', it goes back to normal.

i need help in solving this issue as im unable to find out where i am going wrong!! kindly do the needful!!

my code:

#include <ArduinoJson.h>
#include <SoftwareSerial.h>
#include <DHT.h>
#define DHTPIN 12 // what pin we're connected to
#define DHTTYPE DHT11 // DHT 11 sensor
DHT dht(DHTPIN, DHTTYPE); //initilize the DHT sensor
int ldr = A0; // LDR connected to A0
int relay = 13;
float h,t;
int rx = 11; // softwareserial rx of arduino is pin 11
int tx = 10; // softwareserial tx of arduino is pin 12
SoftwareSerial mySerial(rx,tx);

int l; // variable to store the value coming from the sensor
int bt = 0; // variable to store incoming BT data

void setup() 
{
  pinMode(relay, OUTPUT);
  pinMode(ldr, INPUT);
  Serial.begin(9600);
  mySerial.begin(9600);
  mySerial.println(" Project FLIP");
  mySerial.println("sensor testing");
  mySerial.println(" DHT11 test!");
  dht.begin();
  delay(2000); 
}

void loop() 
{
  humidity_read();//read humidity value
  temperature_read();//read temperature
  light_read(); //read LDR value
  jason_print();
  relay_control();//control relay by reading serial data 0=off, 1=on
  jason_print();
}

void jason_print()
{
  StaticJsonBuffer<200> temp;
  JsonObject& root = temp.createObject();
  root["humidity"] = h;
  root["temp"] = t;
  root["light"] = l;
  root.printTo(Serial);
  Serial.println();
  delay(1000);
}

void humidity_read()
{
  h = dht.readHumidity(); //
}

void temperature_read()
{
  t = dht.readTemperature(); // Read temperature as Celsius (the default)
}

void relay_control()
{
  if (Serial.available() > 0)
  {
    bt = Serial.read();
    if (bt == '1')
    {
      digitalWrite(relay, HIGH);
    }
    else if (bt == '0')
    {
      digitalWrite(relay, LOW);
    }
  }
}
void light_read()
{
  l = analogRead(ldr); //Read LDR value
}

Abhay Bharadwaj Abhay Bharadwaj · Accepted Answer · 2015-10-01T17:14:01

i tried using software serial concept and the same code seems to be working perfectly!! i connected a HC-05 BT module to D10 & 11 pins of arduino and am successfully able to control the relay using my mobile. also, no interference with the json data that is also being transmitted..

but, i still dont know why there is a problem if im using the serial monitor of arduino IDE to do the same operation..

how to send data serially and simultaneously read serial data using json library

1 Answers