BeamNG: GameRawData.ShowLights Value(s)

I ended up using Javascript. Here is my example for 12 relays, BMW E36 Cluster. Everything with GameData.Turn is not assigned to a relay.

Arduino Uno

var DL_SHIFT = 1
var DL_FULLBEAM = 2
var DL_HANDBRAKE = 4
var DL_PITSPEED = 8
var DL_TC = 16
var DL_SIGNAL_L = 32
var DL_SIGNAL_R = 64
var DL_SIGNAL_ANY = 128
var DL_OILWARN = 256
var DL_BATTERY = 512
var DL_ABS = 1024

if ($prop('GameData.Turn7') & DL_SHIFT ) var var1=0; else var1=1;
if ($prop('GameRawData.ShowLights') & DL_SIGNAL_L) var var2=0; else var2=1;
if ($prop('GameData.Turn9') & DL_TC) var var3=0; else var3=1;
if ($prop('GameData.Turn10') & DL_TC) var var4=0; else var4=1;
if ($prop('GameRawData.ShowLights') & DL_ABS) var var5=0; else var5=1;
if ($prop('GameRawData.ShowLights') & DL_BATTERY) var var6=0; else var6=1;
if ($prop('GameData.Turn13') & DL_TC) var var7=0; else var7=1;
if ($prop('GameData.TurnA0') & DL_TC) var var8=0; else var8=1;
if ($prop('GameData.TurnA1') & DL_TC) var var9=0; else var9=1;
if ($prop('GameRawData.ShowLights') & DL_HANDBRAKE) var var10=0; else var10=1;
if ($prop('GameRawData.ShowLights') & DL_OILWARN) var var11=0; else var11=1;
if ($prop('GameRawData.ShowLights') & DL_FULLBEAM) var var12=0; else var12=1;
if ($prop('GameRawData.ShowLights') & DL_SIGNAL_R) var var13=0; else var13=1;


return (var1 + ";" + var2 + ";" + var3 + ";" + var4 + ";" + var5 + ";" + var6 + ";" + var7 + ";" + var8 + ";" + var9 + ";" + var10 + ";" + var11 + ";" + var12 + ";" + var13);

this is the shcustomprotocol.h

#ifndef __SHCUSTOMPROTOCOL_H__
#define __SHCUSTOMPROTOCOL_H__

#include <Arduino.h>

class SHCustomProtocol {
private:

public:

  /*
  CUSTOM PROTOCOL CLASS
  SEE   https://github.com/zegreatclan/SimHub/wiki/Custom-Arduino-hardware-support  

  GENERAL RULES :
    - ALWAYS BACKUP THIS FILE, reinstalling/updating SimHub would overwrite it with the default version.
    - Read data AS FAST AS POSSIBLE in the read function
    - NEVER block the arduino (using delay for instance)
    - Make sure the data read in "read()" function READS ALL THE DATA from the serial port matching the custom protocol definition
    - Idle function is called hundreds of times per second, never use it for slow code, arduino performances would fall
    - If you use library suspending interrupts make sure to use it only in the "read" function when ALL data has been read from the serial port.
      It is the only interrupt safe place

  COMMON FUNCTIONS :
    - FlowSerialReadStringUntil('\n')
      Read the incoming data up to the end (\n) won't be included
    - FlowSerialReadStringUntil(';')
      Read the incoming data up to the separator (;) separator won't be included
    - FlowSerialDebugPrintLn(string)
      Send a debug message to simhub which will display in the log panel and log file (only use it when debugging, it would slow down arduino in run conditions)

  */
int p7;
int p8;
int p9;
int p10;
int p11;
int p12;
int p13;
int pA0;
int pA1;
int pA2;
int pA3;
int pA4;
int pA5;

int PINHEAD7 = 7;
int PINHEAD8 = 8;
int PINHEAD9 = 9;
int PINHEAD10= 10;
int PINHEAD11= 11;
int PINHEAD12= 12;
int PINHEAD13= 13;
int PINHEADA0 = A0;
int PINHEADA1 = A1;
int PINHEADA2 = A2;
int PINHEADA3 = A3;
int PINHEADA4 = A4;
int PINHEADA5 = A5;


  // Called when starting the arduino (setup method in main sketch)
  // nicht 2,3,4,5,6

  void setup() {
pinMode(PINHEAD7,OUTPUT);
pinMode(PINHEAD8,OUTPUT);
pinMode(PINHEAD9, OUTPUT);
pinMode(PINHEAD10,OUTPUT);
pinMode(PINHEAD11,OUTPUT);
pinMode(PINHEAD12,OUTPUT);
pinMode(PINHEAD13,OUTPUT);
pinMode(PINHEADA0, OUTPUT);
pinMode(PINHEADA1,OUTPUT);
pinMode(PINHEADA2, OUTPUT);
pinMode(PINHEADA3,OUTPUT);
pinMode(PINHEADA4, OUTPUT);
pinMode(PINHEADA5,OUTPUT);

digitalWrite(PINHEAD7,HIGH);
digitalWrite(PINHEAD8,HIGH);
digitalWrite(PINHEAD9, HIGH);
digitalWrite(PINHEAD10,HIGH);
digitalWrite(PINHEAD11,HIGH);
digitalWrite(PINHEAD12,HIGH);
digitalWrite(PINHEAD13,HIGH);
digitalWrite(PINHEADA0, HIGH);
digitalWrite(PINHEADA1,HIGH);
digitalWrite(PINHEADA2, HIGH);
digitalWrite(PINHEADA3,HIGH);
digitalWrite(PINHEADA4, HIGH);
digitalWrite(PINHEADA5,HIGH);

 
  }

  // Called when new data is coming from computer
  void read() {

  int p7 = FlowSerialReadStringUntil(';').toInt();
  int p8 = FlowSerialReadStringUntil(';').toInt();
  int p9 = FlowSerialReadStringUntil(';').toInt();
  int p10 = FlowSerialReadStringUntil(';').toInt();
  int p11 = FlowSerialReadStringUntil(';').toInt();
  int p12 = FlowSerialReadStringUntil(';').toInt();
  int p14 = FlowSerialReadStringUntil(';').toInt();
  int pA0 = FlowSerialReadStringUntil(';').toInt();
  int pA1 = FlowSerialReadStringUntil(';').toInt();
  int pA2 = FlowSerialReadStringUntil(';').toInt();
  int pA3 = FlowSerialReadStringUntil(';').toInt();
  int pA4 = FlowSerialReadStringUntil(';').toInt();
  int pA5 = FlowSerialReadStringUntil(';').toInt();

/*

if(p7 == 0)
 {
 digitalWrite(PINHEAD7, LOW);
} else {
digitalWrite(PINHEAD7, HIGH);
}
*/
 
if(p8 == 1)
 {
 digitalWrite(PINHEAD8, HIGH);
} else {
digitalWrite(PINHEAD8, LOW);
}

if (p9 == 0) {
digitalWrite(PINHEAD9, LOW);
} else {
  digitalWrite(PINHEAD9, HIGH);
}

/*if(p10 == 0)
 {
 digitalWrite(PINHEAD10, LOW);
} else {
digitalWrite(PINHEAD10, HIGH);
}
*/
 
if(p11 == 1)
 {
 digitalWrite(PINHEAD11, HIGH);
} else {
digitalWrite(PINHEAD11, LOW);
}

if (p12 == 0) {
digitalWrite(PINHEAD12, LOW);
} else {
  digitalWrite(PINHEAD12, HIGH);
}

if (p13 == 0) {
digitalWrite(PINHEAD13, LOW);
} else {
  digitalWrite(PINHEAD13, HIGH);
}  

if (pA0 == 0) {
digitalWrite(PINHEADA0, LOW);
} else {
  digitalWrite(PINHEADA0, HIGH);
}

if (pA1 == 0) {
digitalWrite(PINHEADA1, LOW);
} else {
  digitalWrite(PINHEADA1, HIGH);
}  

if (pA2 == 0) {
digitalWrite(PINHEADA2, LOW);
} else {
  digitalWrite(PINHEADA2, HIGH);
}

if (pA3 == 0) {
digitalWrite(PINHEADA3, LOW);
} else {
  digitalWrite(PINHEADA3, HIGH);
}  

if (pA4 == 0) {
digitalWrite(PINHEADA4, LOW);
} else {
  digitalWrite(PINHEADA4, HIGH);
}

if (pA5 == 0) {
digitalWrite(PINHEADA5, LOW);
} else {
  digitalWrite(PINHEADA5, HIGH);
}  


  }

  // Called once per arduino loop, timing can't be predicted, 
  // but it's called between each command sent to the arduino
  void loop() {


  
  }

  // Called once between each byte read on arduino,
  // THIS IS A CRITICAL PATH :
  // AVOID ANY TIME CONSUMING ROUTINES !!!
  // PREFER READ OR LOOP METHOS AS MUCH AS POSSIBLE
  // AVOID ANY INTERRUPTS DISABLE (serial data would be lost!!!)
  void idle() {
  }
};

#endif

Thank you very much for your reply, I ended up doing it slightly differently but this helped me understand what to do with the protocl message binding in Javascript!

Here's my solution, mine differs slightly due to a value of 1 requiring the digital write to be LOW, which turns ON the light:

Protocol Message Binding

var DL_FULLBEAM = 2
var DL_HANDBRAKE = 4

if ($prop('TurnIndicatorLeft')) var left=1; else left=0;
if ($prop('TurnIndicatorRight')) var right=1; else right=0;
if ($prop('GameRawData.ShowLights') & DL_FULLBEAM) var fullBeam=1; else fullBeam=0;
if ($prop('GameRawData.ShowLights') & DL_HANDBRAKE) var handbrake=1; else handbrake=0;


return (left + ';' + right + ';' + fullBeam + ";" + handbrake + ';');

shcustomprotocol.h

#ifndef __SHCUSTOMPROTOCOL_H__
#define __SHCUSTOMPROTOCOL_H__

#include <Arduino.h>

class SHCustomProtocol {
private:

public:


  // game values
  int leftIndicator;
  int rightIndicator;
  int highBeam;
  int handbrake;

  // pins
  int leftIndicatorPin = 13;
  int rightIndicatorPin = 12;
  int highBeamPin = 11;
  int handbrakePin = 10;

	// Called when starting the arduino (setup method in main sketch)
	void setup() {
    
    // set pin as outputs
    pinMode(leftIndicatorPin, OUTPUT);
    pinMode(rightIndicatorPin, OUTPUT);
    pinMode(highBeamPin, OUTPUT);
    pinMode(handbrakePin, OUTPUT);

    // set default values to off
    // HIGH = off, assuming relay power connection is "normally-open"
    digitalWrite(leftIndicatorPin, HIGH);
    digitalWrite(rightIndicatorPin, HIGH);
    digitalWrite(highBeamPin, HIGH);
    digitalWrite(handbrakePin, HIGH);
	}

	// Called when new data is coming from computer
	void read() {

    // read values from custom protcol
    // IMPORTANT: Ensure custom protcol has values in this specific order!
    leftIndicator = FlowSerialReadStringUntil(';').toInt();
    rightIndicator = FlowSerialReadStringUntil(';').toInt();
    highBeam = FlowSerialReadStringUntil(';').toInt();
    handbrake = FlowSerialReadStringUntil(';').toInt();

    // Debug information
    FlowSerialDebugPrintLn("leftIndicator Value: " + String(leftIndicator));
    FlowSerialDebugPrintLn("rightIndicator Value: " + String(rightIndicator));
    FlowSerialDebugPrintLn("highBeam Value: " + String(highBeam));
    FlowSerialDebugPrintLn("Handbrake Value: " + String(handbrake));

    // Write pin values
    // TODO: need logic for hazard lights?
    if(leftIndicator == 1) {
      digitalWrite(leftIndicatorPin, LOW);
    } else {
      digitalWrite(leftIndicatorPin, HIGH);
    }

    if(rightIndicator == 1) {
      digitalWrite(rightIndicatorPin, LOW);
    } else {
      digitalWrite(rightIndicatorPin, HIGH);
    }

    if(highBeam == 1) {
      digitalWrite(highBeamPin, LOW);
    } else {
      digitalWrite(highBeamPin, HIGH);
    }

    if(handbrake == 1) {
      digitalWrite(handbrakePin, LOW);
    } else {
      digitalWrite(handbrakePin, HIGH);
    }
    
	}

	// Called once per arduino loop, timing can't be predicted, 
	// but it's called between each command sent to the arduino
	void loop() {
	}

	// Called once between each byte read on arduino,
	// THIS IS A CRITICAL PATH :
	// AVOID ANY TIME CONSUMING ROUTINES !!!
	// PREFER READ OR LOOP METHOS AS MUCH AS POSSIBLE
	// AVOID ANY INTERRUPTS DISABLE (serial data would be lost!!!)
	void idle() {
	}
};

#endif