Freematics Forum

Greetings,

I use "Freematics OBD-II UART Adapter V2 (for Arduino)" on my arduino mega 2560.

RED Power -> VIN
BLACK GND -> GND
White RX -> D0
Green TX -> D1

I use this code:
#include <OBD2UART.h>

COBD obd;

void setup(){
Serial.begin(9600);
Serial.println("Setup.start");
// we'll use the debug LED as output
pinMode(13, OUTPUT);
// start communication with OBD-II adapter
obd.begin();
// initiate OBD-II connection until success
while (!obd.init()){
Serial.print(".");
};
Serial.println("Setup.end");
}

void loop(){
int value;
// save engine RPM in variable 'value', return true on success
if (obd.readPID(PID_RPM, value)) {
// light on LED on Arduino board when the RPM exceeds 3000
if(value > 3000){
Serial.println("3000");
digitalWrite(13, HIGH );
}else{
digitalWrite(13, LOW);
}

}
}

When start the engine, the blue light's Freematics module is power on, some time later, it power off...

And arduino's serial output is:

Setup.start
......................

I have test with 3 arduino mega, all have the same result.

My vehicle is WV Up 2017.

What is wrong?

Best regards

Looks like the adapter failed to connect to OBD of your car. Make sure your car has a supported protocol. You can try manually set a protocol by setting argument of init().

@stanley, thanks for your reply:

Now work, shared infor:

For ARDUINO MEGA 2560 on VW UP 2017

RED Power -> VIN
BLACK GND -> GND
White RX -> D18
Green TX -> D19

[OBD2UART.cpp]
byte COBD::begin(){
Serial.println("COBD::begin");
//long baudrates[] = {2000000,1000000,500000,250000,230400,115200,74880,57600,38400,19200,9600,4800,2400,1200,600,300};
long baudrates[] = {38400};
byte version = 0;
for (byte n = 0; n < sizeof(baudrates) / sizeof(baudrates[0]); n++) {
Serial.println("n[" + (String) n + "] baud[" + (String) baudrates[n] + "]");
#ifndef ESP32
OBDUART.begin(baudrates[n]);
#else
OBDUART.begin(baudrates[n], SERIAL_8N1, 16, 17);
#endif
version = getVersion();
if (version != 0) break;
OBDUART.end();
}
return version;
}

So fixed by manually setting serial baudrate. Good to know.