Timeout Issue

[martindo72050]

Hello. I'm sorry to open another issue on this topic, I've been trying to figure this out for a few days now and can't. Probably my inexperience. Anyway my hardware is:

• Arduino Mega
• HC05
• Bafx ELM327

I'm able to connect and retrieve data using AT commands, but I get timeout errors after connecting using the example code. Any ideas?

[PowerBroker2]

I've had timeouts occur, but only rarely. Are you able to get any data at all with the example before getting timeouts? What happens if you edit the CPP file to follow this configuration?

[martindo72050]

No data before timeouts. I'll try that and let you know.

Edit: Sorry for the dumb question (I'm very new to this stuff), where in the file do I enter that configuration? Do I replace the commands in the initialize function like this:

    sendCommand("AT Z");
    delay(100);

sendCommand("AT E0");
delay(100);

sendCommand("AT S0");
delay(100);

sendCommand("AT SP0");
delay(100);

[PowerBroker2]

You can use the macros from the header file, but I think you can do what you posted instead

[martindo72050]

Tried it and still get the same issue

[PowerBroker2]

You said you can get data using AT commands. Can you provide that list of AT commands and their responses?

[martindo72050]

Yes. I actually only used the AT commands for setting up the HC05, then got it out of AT mode and started simply typing the PIDs. Here I repeatedly typed 010C (rpm) and got this response:

[PowerBroker2]

In that case, try getting rid of all AT commands in the begin() method and see if that fixes it

[martindo72050]

Same result. Here is my current Arduino code:

#include "ELMduino.h"



#define ELM_PORT Serial1


ELM327 myELM327;


uint32_t rpm = 0;


void setup()
{
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, HIGH);

  Serial.begin(38400);
  ELM_PORT.begin(38400);

  Serial.println("Attempting to connect to ELM327...");

  if (!myELM327.begin(ELM_PORT))
  {
    Serial.println("Couldn't connect to OBD scanner");
    while (1);
  }

  Serial.println("Connected to ELM327");
}


void loop()
{
  float tempRPM = myELM327.rpm();

  if (myELM327.status == ELM_SUCCESS)
  {
    rpm = (uint32_t)tempRPM;
    Serial.print("RPM: "); Serial.println(rpm);
  }
  else
  {
    Serial.print(F("\tERROR: "));
    Serial.println(myELM327.status);
    delay(100);
  }  
  delay(1000);
}

[brainfoolong]

Hi, i also have the same problem. If looked into the elmduino code and i found something that i can't explain. Currently it is so: After successfull initialization, once you get a ELM_TIMEOUT or ELM_UNABLE_TO_CONNECT after any command, you are stuck in that status and can't send any other commands.

It's because in current code, the connected flag is set to false on the begin of every sendCommand ->

ELMduino/src/ELMduino.cpp

Line 508 in 342fc1e

connected = false;

This flag is only updated to true when you have received any success request (no timeout or unable to connect) ->

ELMduino/src/ELMduino.cpp

Line 554 in 342fc1e

connected = true;

And the problem with this is, every call to queryPID, which you basically use for every data you want, require a connected = true ->

ELMduino/src/ELMduino.cpp

Line 360 in 342fc1e

if (connected)

But this connected will never be true again, by only using a queryPID command. You have to call sendCommand to properly send a command, doesn't matter what connected status you have.

I've created a pull request, maybe this is helpful for someone and maybe this will be merged by the maintainer.

#47

[PowerBroker2]

Oh dang, good catch! I'll take a look at the PR. I've had trouble with many users (including myself, actually) having this timeout error issue, but could never figure it out - I hope this bug is the root of the issue.

[PowerBroker2]

This should be resolved with release 2.3.2