Hi all
I am trying to play around with an ELM327 OBD2 bluetooth adapter on my old Honda Civic, but encountered a problem with bluetooth paring.
Here is the schema:
And here is the code:
#include <LiquidCrystal_I2C.h>
#include <SoftwareSerial.h>
#include <Wire.h>
#define RxD 10
#define TxD 11
LiquidCrystal_I2C lcd(0x3F, 16, 2);
SoftwareSerial SoftSerial(RxD,TxD);
byte inData;
char inChar;
String BuildINString="";
String DisplayString="";
String WorkingString="";
long DisplayValue;
long A;
void setup() {
lcd.init();
lcd.backlight();
lcd.home();
lcd.setCursor(0, 0);
lcd.print("Honda Civic VII");
delay(3000);
lcd.clear();
//********************************************************************
//Check if ELM327 responded
Retry:
lcd.setCursor(0, 0);
lcd.print(" ");
lcd.setCursor(0, 1);
lcd.print("Connecting...... ");
//Set up Serial communication at 9600 baud
SoftSerial.begin(9600); //initialize Serial
SoftSerial.println("ATZ");
lcd.setCursor(0, 0);
lcd.print("OBD2");
delay(2000);
ReadData();
// If used substring(1,4)=="ATZ" needed a space before ATZ in Serial Monitor and it did not work
if (BuildINString.substring(1,3)=="TZ") // MIATA RESPONSE TO ATZ IS ATZ[[[ELM327 V1.5 OR AT LEAST THAT IS WHAT ARDUINO HAS IN THE BUFFER
{
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Welcome");
lcd.setCursor(9, 0);
//lcd.print(BuildINString); //Echo response to screen "Welcome ELM327"
lcd.setCursor(0, 1);
lcd.print("Connection OK ");
delay(1500);
lcd.clear();
}
else
{
lcd.setCursor(0, 0);
lcd.print("Error ");
lcd.setCursor(0, 1);
lcd.print("No Connection! ");
delay(1500);
lcd.clear();
goto Retry;
}
//*****************************************************************
//Added this from the test Code
SoftSerial.println("0100"); // Works with This only
lcd.setCursor(0, 0);
lcd.print("Initialzing....."); //Initialize BUS //lcd.print("0100 Sent");
delay(4000);
ReadData();
lcd.setCursor(0, 0); //Added 12-10-2016
lcd.print("Initialized....."); //Added 12-10-2016
delay(1000);
lcd.clear();
}
void loop() {
// Added to display Coolant Temp
lcd.setCursor(0, 0);
lcd.print("Coolant Temp ");
//resets the received string to NULL Without it it repeated last string.
BuildINString = "";
SoftSerial.println("0105"); // Send Coolant PID request 0105
//SoftSerial.flush(); //Not sure if it's needed*********************************************
delay(1000);
// Receive complete string from the serial buffer
ReadData(); //replaced below code
// Parse the received string, retrieve only the hex value for temperature Example: 32 is the 11 and 12th character
// 0105[41 05 32 Correct value reading back 10 degrees. (11,13 or even 11,14 works)
WorkingString = BuildINString.substring(11,13);
A = strtol(WorkingString.c_str(),NULL,16); //convert hex to decimnal
DisplayValue = A;
DisplayString = String(DisplayValue - 40) + " C "; // Subtract 40 from decimal to get the right temperature
lcd.setCursor(0, 1);
lcd.print(DisplayString);
delay(500);
//Check if if over 100 C ******************************************************
int B;
B = DisplayString.toInt(); //Convert String to Integer .toInt()
if (B >= 100){ //Check if if over 100 C
// ------- Quick 3 blinks of backlight -------------
for(int i = 0; i< 3; i++)
{
lcd.display(); //For I2C use lcd.backlight
delay(250);
lcd.noDisplay(); //For I2C use lcd.noBacklight
delay(250);
}
lcd.display(); // finish with backlight on //For I2C use lcd.backlight
}
}
//Read Data Function ***********************************************************
void ReadData()
{
BuildINString="";
while(SoftSerial.available() > 0)
{
inData=0;
inChar=0;
inData = SoftSerial.read();
inChar=char(inData);
BuildINString = BuildINString + inChar;
}
}
Before, the HC-05 bluetooth was switched to AT mode and all that should be, set:
AT+BIND=0019,6D,3292EF
OK
AT+BIND?
+BIND:19:6d:3292ef
OK
AT+CMODE?
+CMOD:1
OK
AT+CMODE=0
OK
AT+ROLE?
+ROLE:1
OK
AT+PSWD?
+PSWD:1234
OK
But, according to the LED blinking on the HC-05 module, it can't pair with ELM327 adapter (adapter is fully working, the smartphone connects to it without any issues)
LED blinkage Youtube link
Any advises would be very helpful, thank you in advance!