Beginner question: using strings to control pins

Using Arduino Programming Questions
1

Hello,

I'm just starting with Arduino with some experience in other languages (but little in C++). I'm sorry if this question should be asked somewhere else, I did the obligatory searching through this forum and others, but couldn't find anything to help out.

Basically I'm trying to write code that, based on a variable will control LED's connected to different pins. As the code currently stands, the variables I'm using are Strings. I imagine this is the root of my problem, but don't know what to do about it.

An example bit of code is:

int Rled1 = 12;
int Rled2 = 11;

void Setup(){
  pinMode(Rled1, OUTPUT);
  pinMode(Rled2, OUTPUT);
}
void loop(){
  //i have a segment of code here I can confirm is working, through the serial monitor.  get's me to:
  if (var == 1){
    String red_led = "Rled";
    red_led.concat(var); //up till here works
    digitalWrite(red_led, 255);
  }
}

The last line of my code gives the error:
" cannot convert 'String' to 'uint8_t' for argument '1' to 'void digitalWrite(uint8_t, uint8_t)'".

Any help would be greatly appreciated.

Thanks

2

The Arduino has no idea that the String "Rled1" has anything to do with the int variable Rled1. All the Arduino knows about Rled1 is that it is 2 bytes and has an address. You need to create a Hash table or use a series of if/else statements.

3

Thanks Archh. I guess what I'm getting at is: Is there any way to use a variable to assign which pin to control? If so, am I able to use/convert a string to be this variable?

Again, thanks.

4

Hainsy:
Is there any way to use a variable to assign which pin to control?

Yes.

If so, am I able to use/convert a string to be this variable?

Again, thanks.

I just answered that in my last post.

5

Thanks again... you made me realize the far easier way was to use arrays where the call variable was equal to the pin to call.