Help! 'D2' was not declared in this scope

Using Arduino Programming Questions
1

Hello all,
I am working on a project to make a resistive steering wheel control adapter to integrate an aftermarket head unit into a chevy silverado. The truck has resistive SWC, but it is designed for sourcing not sinking. The head unit wants sinking not sourcing. Using voltage dividers and diodes, I believe I have the hardware figured out, I am struggling with getting the code to compile. I understand that Variables should be defined within the function which they are used. I also thought that I understood that Pins were predefined in association with the board(an Arduino Nano in this case). I keep getting "not declared in this scope", for every pin. I am not sure where the break down is here or what I am getting wrong. I would appreciate any guidance.

void setup()
{
  Serial.begin(9600);
  pinMode(D2, OUTPUT); 
  pinMode(D3, OUTPUT); 
  pinMode(D4, OUTPUT); 
  pinMode(D5, OUTPUT); 
  pinMode(D6, OUTPUT); 
  pinMode(D7, OUTPUT); 
  pinMode(D8, OUTPUT); 
  digitalWrite(D2, high);
  digitalWrite(D3, high);
  digitalWrite(D4, high);
  digitalWrite(D5, high);
  digitalWrite(D6, high);
  digitalWrite(D7, high);
  digitalWrite(D8, high);
}


void loop()
{

  int input_value = analogRead(A0);
      if (input_value > 975 ) { 
        digitalWrite(D2, low);
        delay(10);
        digitalWrite(D2, high);}
     else if (input_value < 955 && input_value > 920) { 
        digitalWrite(D3, low);
        delay(10);
       digitalWrite(D3, high);}
     else if (input_value < 805 && input_value > 765) {
        digitalWrite(D4, low);
        delay(10);
        digitalWrite(D4, high);}
      else if (input_value < 680 && input_value > 620) {
        digitalWrite(D5, low);
        delay(10);
        digitalWrite(D5, high);}
     else if (input_value < 580 && input_value > 520) {
        digitalWrite(D6, low);
        delay(10);
       digitalWrite(D6, high);}
     else if (input_value < 480 && input_value > 420) {
       digitalWrite(D7, low);
       delay(10);
       digitalWrite(D7, high);}
     else (input_value < 370 && input_value > 310) {
       digitalWrite(D8, low);
       delay(10);
       digitalWrite(D8, high);}
  delay(10);
  Serial.println(input_value);    
    }
2

Lose the D's. You just need the number.

3

Try:

void setup() {
   Serial.begin(9600);
   pinMode(2, OUTPUT);
   pinMode(3, OUTPUT);
   pinMode(4, OUTPUT);
   pinMode(5, OUTPUT);
   pinMode(6, OUTPUT);
   pinMode(7, OUTPUT);
   pinMode(8, OUTPUT);
   digitalWrite(2, HIGH);
   digitalWrite(3, HIGH);
   digitalWrite(4, HIGH);
   digitalWrite(5, HIGH);
   digitalWrite(6, HIGH);
   digitalWrite(7, HIGH);
   digitalWrite(8, HIGH);
}


void loop() {

   int input_value = analogRead(A0);
   if( input_value > 975 ) {
      digitalWrite(2, LOW);
      delay(10);
      digitalWrite(2, HIGH);
   } else if (input_value < 955 && input_value > 920) {
      digitalWrite(3, LOW);
      delay(10);
      digitalWrite(3, HIGH);
   } else if (input_value < 805 && input_value > 765) {
      digitalWrite(4, LOW);
      delay(10);
      digitalWrite(4, HIGH);
   } else if (input_value < 680 && input_value > 620) {
      digitalWrite(5, LOW);
      delay(10);
      digitalWrite(5, HIGH);
   } else if (input_value < 580 && input_value > 520) {
      digitalWrite(6, LOW);
      delay(10);
      digitalWrite(6, HIGH);
   } else if (input_value < 480 && input_value > 420) {
      digitalWrite(7, LOW);
      delay(10);
      digitalWrite(7, HIGH);
   } else if (input_value < 370 && input_value > 310) {
      digitalWrite(8, LOW);
      delay(10);
      digitalWrite(8, HIGH);
   }
   delay(10);
   Serial.println(input_value);
}
4

I attempted the suggested changes, the following is my fault log.

EDIT: I just realized in your suggestion you changed HIGH and LOW to all caps, I am still missing that, will try again.

Arduino: 1.8.5 (Windows 7), Board: "Arduino Nano, ATmega328P (Old Bootloader)"

Build options changed, rebuilding all
C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino: In function 'void setup()':

Chevy_Head_unit_SWC_button:19: error: 'high' was not declared in this scope

   digitalWrite(2, high);

                   ^~~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:19:19: note: suggested alternative: 'sinh'

   digitalWrite(2, high);

                   ^~~~

                   sinh

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino: In function 'void loop()':

Chevy_Head_unit_SWC_button:34: error: 'low' was not declared in this scope

         digitalWrite(2, low);

                         ^~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:34:25: note: suggested alternative: 'pow'

         digitalWrite(2, low);

                         ^~~

                         pow

Chevy_Head_unit_SWC_button:36: error: 'high' was not declared in this scope

         digitalWrite(2, high);}

                         ^~~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:36:25: note: suggested alternative: 'sinh'

         digitalWrite(2, high);}

                         ^~~~

                         sinh

Chevy_Head_unit_SWC_button:38: error: 'low' was not declared in this scope

         digitalWrite(3, low);

                         ^~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:38:25: note: suggested alternative: 'pow'

         digitalWrite(3, low);

                         ^~~

                         pow

Chevy_Head_unit_SWC_button:40: error: 'high' was not declared in this scope

        digitalWrite(3, high);}

                        ^~~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:40:24: note: suggested alternative: 'sinh'

        digitalWrite(3, high);}

                        ^~~~

                        sinh

Chevy_Head_unit_SWC_button:42: error: 'low' was not declared in this scope

         digitalWrite(4, low);

                         ^~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:42:25: note: suggested alternative: 'pow'

         digitalWrite(4, low);

                         ^~~

                         pow

Chevy_Head_unit_SWC_button:44: error: 'high' was not declared in this scope

         digitalWrite(4, high);}

                         ^~~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:44:25: note: suggested alternative: 'sinh'

         digitalWrite(4, high);}

                         ^~~~

                         sinh

Chevy_Head_unit_SWC_button:46: error: 'low' was not declared in this scope

         digitalWrite(5, low);

                         ^~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:46:25: note: suggested alternative: 'pow'

         digitalWrite(5, low);

                         ^~~

                         pow

Chevy_Head_unit_SWC_button:48: error: 'high' was not declared in this scope

         digitalWrite(5, high);}

                         ^~~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:48:25: note: suggested alternative: 'sinh'

         digitalWrite(5, high);}

                         ^~~~

                         sinh

Chevy_Head_unit_SWC_button:50: error: 'low' was not declared in this scope

         digitalWrite(6, low);

                         ^~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:50:25: note: suggested alternative: 'pow'

         digitalWrite(6, low);

                         ^~~

                         pow

Chevy_Head_unit_SWC_button:52: error: 'high' was not declared in this scope

        digitalWrite(6, high);}

                        ^~~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:52:24: note: suggested alternative: 'sinh'

        digitalWrite(6, high);}

                        ^~~~

                        sinh

Chevy_Head_unit_SWC_button:54: error: 'low' was not declared in this scope

        digitalWrite(7, low);

                        ^~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:54:24: note: suggested alternative: 'pow'

        digitalWrite(7, low);

                        ^~~

                        pow

Chevy_Head_unit_SWC_button:56: error: 'high' was not declared in this scope

        digitalWrite(7, high);}

                        ^~~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:56:24: note: suggested alternative: 'sinh'

        digitalWrite(7, high);}

                        ^~~~

                        sinh

Chevy_Head_unit_SWC_button:58: error: 'low' was not declared in this scope

        digitalWrite(8, low);

                        ^~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:58:24: note: suggested alternative: 'pow'

        digitalWrite(8, low);

                        ^~~

                        pow

Chevy_Head_unit_SWC_button:60: error: 'high' was not declared in this scope

        digitalWrite(8, high);}

                        ^~~~

C:\Users\AL\Documents\Arduino\Chevy_Head_unit_SWC_button\Chevy_Head_unit_SWC_button.ino:60:24: note: suggested alternative: 'sinh'

        digitalWrite(8, high);}

                        ^~~~

                        sinh

exit status 1
'high' was not declared in this scope

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.
5

Thank you for the help. could some one explain the situation with the pin naming? Analog pins are A0,A1,etc... but Digital Pins are just their associated number?
Thank you.

6

In some cores, the digital pins are also assigned D# numbers (often to make native GPIO numbers more like the original AVR pin number assignments). But it's not done in the AVR core.