help on code conversion from ELMduino 2.x to 3.x

[miguelos6]

Hi folks

For long time I used successfuly the ELMduino 2.x code, with custom PIDs (suggested by PowerBroker2) as below :

  if (myELM327.queryPID(34, 12345))
  {
    int16_t tempKm = myELM327.findResponse();    
    if (myELM327.status == ELM_SUCCESS) { km = tempKm;}
    else printError();
  }

I tried to understand and convert the same to ELMduino 3.x but the results are gibberish (not the same as on ELMduino 2.x)

my approach

  float tempKm = myELM327.processPID(34, 12345, 1, 1);
  if (myELM327.nb_rx_state == ELM_SUCCESS) { km = (int16_t)tempKm; }
  else if (myELM327.nb_rx_state != ELM_GETTING_MSG)
    myELM327.printError();

Can someone help me on this ?
I'd like to test new features like DTC from 3.x...

[PowerBroker2]

Can you post the entire sketch plus the debug output? Also note that the examples have been updated along with the codebase to help the 2.x to 3.x conversion

[miguelos6]

I don't have debug yet, I was dumping the results on screen only.

I didn't manage to run any ELM emulator successfully :/
ELMulator from https://github.com/jimwhitelaw/ELMulator throws an error for everything while connected with android app

I just thought there is some major flaw in my understanding of above code...

[miguelos6]

the sketch is pretty much modified version of what we discussed years ago :)
#4 (comment)

Will try and get the dump tomorrow...

I guess I may found what the issue is (without connecting to real OBD, but running debugs)
as we found years ago

#4 (comment)
query 223039 (PID 34, 12345 dec // hex 0x22 0x3039)
reply 623039019F

but in 3.x version and above code I can see it's converted to 2230391 (1 at the end...) :
20:11:51.065 -> Service: 34
20:11:51.065 -> PID: 12345
20:11:51.065 -> Long query detected
20:11:51.065 -> Query string: 2230391
20:11:51.065 -> Clearing input serial buffer
20:11:51.065 -> Sending the following command/query: 2230391

[miguelos6]

debug from ESP module :
pastebin

[miguelos6]

I think this is correct output of debug
pastebin2

piece of code reading and displaying values below (first I assigned values from -9 to -5)

float tempRPM = myELM327.rpm();
if (myELM327.nb_rx_state == ELM_SUCCESS) { rpm = (int16_t)tempRPM; }
Serial.print("rpm "); Serial.println(rpm);

float tempKm = myELM327.processPID(34, 12345, 1, 1);
if (myELM327.nb_rx_state == ELM_SUCCESS) { km = (int16_t)tempKm; }
Serial.print("km "); Serial.println(km);

float tempLitersLeft = myELM327.processPID(34, 4906, 1, 1);
if (myELM327.nb_rx_state == ELM_SUCCESS) { litersLeft = (int16_t)tempLitersLeft; }
Serial.print("Li "); Serial.println(litersLeft);

etc etc.

[jimwhitelaw]

I think I may know what's happening there - the number of payload characters is being miscalculated in the response. In previous examples of custom PID queries, the ECU would add extra padding in the response, but yours is not doing that so then the number of expected payload chars is incorrect and you're getting the warning message and 0 value. I've assigned the issue to myself and I'll work on a fix.

Edit: I've spent some time investigating and what I thought might be happening is not the case. I still don't understand why you see the warning message.

Also, if you believe you have discovered a problem with ELMulator, please file an issue here. thx

[miguelos6]

is there any way I can help ?
just to clarify - same OBD2 module, but with latest ELMduino 2.x works fine. Snippets of code are in first post..

[PowerBroker2]

Please post the entire sketch (in tags!) you're running so that we can better make sense of what's happening in the debug log

[miguelos6]

with removed unneccessary display code..

#include <TFT_eSPI.h> // Graphics and font library for ST7735 driver chip
#include <SPI.h>
#include "BluetoothSerial.h"
#include "ELMduino.h"

#define ELM_PORT SerialBT
#define ESP_BLUETOOTH_NAME "ESP32-M1" // module name here
#define READDELAY 500
// V-LINK real => 00:1D:A5:20:BC:21
  uint8_t btaddress[6]  = {0x30, 0x3D, 0x35, 0x30, 0x3C, 0x31};

#define OBD_NAME "V-LINK"


// ---------- ENABLE TESTING HERE -------- //
bool testing = false;

BluetoothSerial SerialBT;
ELM327 myELM327;

TFT_eSPI tft = TFT_eSPI(); // Invoke custom library

  int16_t rpm=-9, soot=-8, burn=-7, km=-6, litersLeft=-5;
  
void setup() {

  delay(500);
  Serial.begin(115200);
  
  if (not testing) {
  ELM_PORT.begin(ESP_BLUETOOTH_NAME, true); // enables debugging
  }
  
  delay(500);

  if (not testing) {

  if (!ELM_PORT.connect(btaddress))
  {
    Serial.println("Mdeb: \tCouldn't connect to OBD scanner - Phase 1");
      delay(READDELAY);
  }


  if (!myELM327.begin(ELM_PORT, true, 2000)) // debug = true
  {
    Serial.println("Mdeb: \tCouldn't connect to OBD scanner - Phase 2");
    delay(READDELAY);
    Serial.println("Mdeb: \tNOT");
  }
  
  Serial.println("Mdeb: \tConnected to ELM327");
  }
}


void loop() {


if (testing) {
    // for testing display only, faking readings here //
    Serial.println(F("Mdeb: \tTesting configured"));
    soot = random(0,99);
    km = random(0,500);
    rpm = random (750,3500);
}

else {  
// read counters

  float tempRPM = myELM327.rpm();
  if (myELM327.nb_rx_state == ELM_SUCCESS) { rpm = (int16_t)tempRPM; }
  Serial.print("rpm "); Serial.println(rpm);

  float tempSoot = myELM327.processPID(34, 13162, 1, 1);
  if (myELM327.nb_rx_state == ELM_SUCCESS) { soot = (int16_t)tempSoot; }
  Serial.print("% "); Serial.println(soot);

  float tempKm = myELM327.processPID(34, 12345, 1, 1);
  if (myELM327.nb_rx_state == ELM_SUCCESS) { km = (int16_t)tempKm; }
  Serial.print("km "); Serial.println(km);

}

// reading ends, now display it all / blink screen

 secondScreen();
  delay(700);
  
}



// ended here
void secondScreen (){
// displaying values      
}

[PowerBroker2]

Since the 3.X version of the code is non-blocking, you can't call the queries for multiple PIDs one after another before ensuring you've either parsed a response or errored one PID at a time (if that makes any sense). Go back to the updated examples to see how to properly query multiple PIDs with the 3.X code.