ELMduino BLE Support

[vdvornichenko]

Hi there,

I built a small Serial wrapper for BLE connection, so now it's possible to use ELMduino with BLE 4.0 OBD dongles.

Tested with OBDLink CX, custom headers and PID are also working fine, you can take a look.

https://github.com/vdvornichenko/obd-ble-serial

[patfelst]

Amazing, great work - well done!

[jimwhitelaw]

This is excellent! I started on something similar but it got sidetracked for various reasons and never finished. Your implementation looks more robust than what I was working on. Nice. This could be useful for other projects as well that need a BLE to Serial library. I'm looking forward to trying this out soon.

[Ldalvik]

Hello, what devices have you tried this on? I tried multiple ESP32S3 Dev Module LCD screens and they all crash when using your example.

[ElettroshockNow]

You are a legend .... I was tired of always having to enter the MAC .... thank you thank you and a thousand thanks
It connects quickly to the odb, but corrupts some data..
However the ELMduino library is able to interpret well (rpm, speed....etc), except for the voltage

es:

08:42:46.198 Clearing input serial buffer
08:42:46.198 Sending the following command/query: AT RV
08:42:46.228 [DEBUG] ELM RESPONSE > AT_RV
08:42:46.231 [DEBUG] ELM RESPONSE > \r
08:42:46.242 [DEBUG] ELM RESPONSE > 13.8V\r\r>
08:42:46.258 	Received char: A
08:42:46.278 	Received char: T
08:42:46.297 	Received char: _
08:42:46.318 	Received char: R
08:42:46.338 	Received char: V
08:42:46.357 	Received char: ?
08:42:46.377 	Received char: \r
08:42:46.397 	Received char: T
08:42:46.417 	Received char: _
08:42:46.438 	Received char: R
08:42:46.457 	Received char: V
08:42:46.478 	Received char: ?
08:42:46.497 	Received char: 1
08:42:46.517 	Received char: 3
08:42:46.538 	Received char: .
08:42:46.558 	Received char: 8
08:42:46.577 	Received char: V
08:42:46.597 	Received char: \r
08:42:46.617 	Received char: \r
08:42:46.643 	Received char: >
08:42:46.643 Delimiter found.
08:42:46.643 All chars received: ATRVTRV13.8V
08:42:46.645 Battery Voltage: 0.00

instead of (connection via MAC)

14:18:14.681 Sending the following command/query: AT RV
14:18:14.693 	Received char: A
14:18:14.693 	Received char: T
14:18:14.693 	Received char: _
14:18:14.693 	Received char: R
14:18:14.698 	Received char: V
14:18:14.698 	Received char: \r
14:18:14.720 	Received char: 1
14:18:14.720 	Received char: 3
14:18:14.720 	Received char: .
14:18:14.720 	Received char: 8
14:18:14.726 	Received char: V
14:18:14.726 	Received char: \r
14:18:14.726 	Received char: \r
14:18:14.731 	Received char: >
14:18:14.731 Delimiter found.
14:18:14.731 All chars received: ATRV13.8V
14:18:14.737 Battery Voltage: 13.80

and small problem: if (!ELM_PORT.connect()) { ------>if false (so with odb powered off) it resets the device

21:40:07.072 -> entry 0x400805b8
21:40:16.757 -> Forming a connection to 
21:40:16.757 -> Guru Meditation Error: Core  1 panic'ed (LoadProhibited). Exception was unhandled.
21:40:16.757 -> 
21:40:16.757 -> Core  1 register dump:
21:40:16.801 -> PC      : 0x400915b3  PS      : 0x00060730  A0      : 0x800db5e8  A1      : 0x3ffcc1d0  
21:40:16.801 -> A2      : 0x3ffcc1ea  A3      : 0x00000005  A4      : 0x00000006  A5      : 0x3ffcc1ea  
21:40:16.801 -> A6      : 0x00000006  A7      : 0x3ffc3cf4  A8      : 0x800e101c  A9      : 0x3ffcc1b0  
21:40:16.801 -> A10     : 0x00000002  A11     : 0x3f403fb8  A12     : 0x00000018  A13     : 0x0000ff00  
21:40:16.801 -> A14     : 0x00ff0000  A15     : 0x3ffc3cf4  SAR     : 0x00000010  EXCCAUSE: 0x0000001c  
21:40:16.824 -> EXCVADDR: 0x00000005  LBEG    : 0x40091ca5  LEND    : 0x40091cb5  LCOUNT  : 0xffffffff  
21:40:16.824 -> 
21:40:16.824 -> 
21:40:16.824 -> Backtrace: 0x400915b0:0x3ffcc1d0 0x400db5e5:0x3ffcc1e0 0x400d26b5:0x3ffcc210 0x400d5ebb:0x3ffcc250 0x400e3f9f:0x3ffcc290 0x40094bc2:0x3ffcc2b0
21:40:16.824 -> 
21:40:16.824 -> 
21:40:16.824 -> 
21:40:16.824 -> 
21:40:16.824 -> ELF file SHA256: b6d7320c9
21:40:16.824 -> 
21:40:17.157 -> Rebooting...
21:40:17.157 -> ets Jun  8 2016 00:22:57
21:40:17.157 -> 
21:40:17.157 -> rst:0xc (SW_CPU_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)

Saluti
Luca

[ElettroshockNow]

SOLVED For the corrupted data passed to elmduino (which still manages to interpret well), I took the liberty of modifying the library "BLEClientSerial.cpp"

static void notifyCallback(
    BLERemoteCharacteristic *pBLERemoteCharacteristic,
    uint8_t *pData,
    size_t length,
    bool isNotify)
{   
    Serial.print("[DEBUG] ELM RESPONSE > ");
    printFriendlyResponse(pData, length);

    // Convertiamo i dati ricevuti in una stringa
    std::string receivedData((char*)pData, length);

    // Se la nuova stringa è già presente alla fine di staticBuffer, evitiamo di concatenarla
    if (staticBuffer.size() < length || staticBuffer.substr(staticBuffer.size() - length) != receivedData) {
        staticBuffer += receivedData;
    }

    //Serial.print("[DEBUG] staticBuffer after append: ");
    //Serial.println(staticBuffer.c_str());
}

printout (ESP32 ELMduino 3.3.2 OBD Vlink connected via BLE )

Clearing input serial buffer
Sending the following command/query: AT RV
[DEBUG] ELM RESPONSE > A
[DEBUG] ELM RESPONSE > T_
[DEBUG] ELM RESPONSE > R
[DEBUG] ELM RESPONSE > V
[DEBUG] ELM RESPONSE > \r
[DEBUG] ELM RESPONSE > 13.9V\r\r>
	Received char: A
	Received char: T
	Received char: _
	Received char: R
	Received char: V
	Received char: \r
	Received char: 1
	Received char: 3
	Received char: .
	Received char: 9
	Received char: V
	Received char: \r
	Received char: \r
	Received char: >
Delimiter found.
All chars received: ATRV13.9V
Battery Voltage: 13.90

[ElettroshockNow]

SOLVED "Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled"
I added a mydevice check "BLEClientSerial.cpp"

bool BLEClientSerial::connect(void)
{
    Serial.println("Forming a connection to ");
    // Controllo che myDevice sia stato trovato durante la scansione BLE
    if (myDevice == nullptr) {
        Serial.println("Errore: Nessun dispositivo BLE trovato! Assicurati che l'OBD sia acceso.");
        return false;
    }
    Serial.println(myDevice->getAddress().toString().c_str());

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