Resistor Value Coding: Higher values will not work

Projects Programming
1

I have this program where it calculates resistor values. It's a really poor code but for the most part it works. My problem comes when my program tries to calculate the third band on the resistor (which goes up to 10M). I know that the values don't read because the value is too high and I'm using a string, but I can't find a way around this problem.

Lab_4_Part_2_attempt_2.ino (6.36 KB)

2

OP's code:

String Colours[] = {"black", "brown", "red", "orange", "yellow", "green", "blue", "violet", "grey", "white", "gold", "silver", "none" };


/****************************************************************************************************FUNCTION PROTOTYPES***************************************************************************************************************************************************/


void setup() {
  Serial.begin(9600);                                                                                                  //Opens communication with the computer for Serial.XYZ functions

}

/********************************************************************************************************Main Program******************************************************************************************************************************************************/

void loop() {

  /******************************************************************************************Variable Declaration and Initialization*****************************************************************************************************************************************/
  String Answers[14];// String declared
  int a = 0, b = 0, c = 0, d = 0;// Variables used to manipulate arrays
  char Again = 0; // Used to start program again
  double ResValue;
  /*******************************************************************************************************MAIN ALGORITHM*****************************************************************************************************************************************************/

  do {
    Serial.print("This program will calculate a resistors value by asking for the four band colours.");
    Serial.print("\n What is the first band colour on your resistor?");

    while (Serial.available() == 0) {}; // Wait for user input
    Answers[a] = Serial.readString();
    Answers[a].toLowerCase();// Force user input to all lowercase
    Serial.print("\n You entered: ");
    Serial.print(Answers[a]); // Print out user input

    if (Answers[a] == "black") { // This will convert the first band colour into a number
      a = 0;
    }
    else if (Answers[a] == "brown") {
      a = 1;
    }
    else if (Answers[a] == "red") {
      a = 2;
    }
    else if (Answers[a] == "orange") {
      a = 3;
    }
    else if (Answers[a] == "yellow") {
      a = 4;
    }
    else if (Answers[a] == "green") {
      a = 5;
    }
    else if (Answers[a] == "blue") {
      a = 6;
    }
    else if (Answers[a] == "violet") {
      a = 7;
    }
    else if (Answers[a] == "grey") {
      a = 8;
    }
    else if (Answers[a] == "white") {
      a = 9;
    }
    else {
      Serial.print("\n You entered an invalid colour");
    }


    Serial.print("\n What is the second band colour on your resistor?");

    while (Serial.available() == 0) {}; // Wait for user input
    Answers[b] = Serial.readString();
    Answers[b].toLowerCase();// Force user input to all lowercase
    Serial.print("\n You entered: ");
    Serial.print(Answers[b]); // Print out user input

    if (Answers[b] == "black") { // This will convert the second band colour into a number
      b = 0;
    }
    else if (Answers[b] == "brown") {
      b = 1;
    }
    else if (Answers[b] == "red") {
      b = 2;
    }
    else if (Answers[b] == "orange") {
      b = 3;
    }
    else if (Answers[b] == "yellow") {
      b = 4;
    }
    else if (Answers[b] == "green") {
      b = 5;
    }
    else if (Answers[b] == "blue") {
      b = 6;
    }
    else if (Answers[b] == "violet") {
      b = 7;
    }
    else if (Answers[b] == "grey") {
      b = 8;
    }
    else if (Answers[b] == "white") {
      b = 9;

    }
    else Serial.print("\n You entered an invalid colour");


    Serial.print("\n What is the third band colour on your resistor?");

    while (Serial.available() == 0) {}; // Wait for user input
    Answers[c] = Serial.readString();
    Answers[c].toLowerCase();// Force user input to all lowercase
    Serial.print("\n You entered: ");
    Serial.print(Answers[c]); // Print out user input

   
    if (Answers[c] == "black") { // This will convert the third band colour into a number
      c = 1;
    }
    else if (Answers[c] == "brown") {
      c = 10;
    }
    else if (Answers[c] == "red") {
      c = 100;
    }
    else if (Answers[c] == "orange") {
      c = 1000;
    }
    else if (Answers[c] == "yellow") {
      c = 10000;
    }
    else if (Answers[c] == "green") {
      c = 100000;
    }
    else if (Answers[c] == "blue") {
      c = 1000000;
    }
    else if (Answers[c] == "violet") {
      c = 10000000;
    }
    else if (Answers[c] == "gold") {
      c = 0.1;
    }
    else if (Answers[c] == "silver") {
      c = 0.01;

    }
    else Serial.print("\n You entered an invalid colour");


    Serial.print("\n What is the fourth band colour on your resistor?");

    while (Serial.available() == 0) {}; // Wait for user input
    Answers[d] = Serial.readString();
    Answers[d].toLowerCase();// Force user input to all lowercase
    Serial.print("\n You entered: ");
    Serial.print(Answers[d]); // Print out user input

    if (Answers[d] == "gold") { // This will convert the fourth band colour into a number
      d = 5;
    }
    else if (Answers[d] == "silver") {
      d = 10;
    }
    else if (Answers[d] == "none") {
      d = 0;
    }
    else Serial.print("\n You entered an invalid colour");

    ResValue = (a * 10 + b) * c; // Calculate the resistors value

    Serial.print("\n The value of your resistor is: ");
    Serial.print(ResValue, 0);
    Serial.print("Ω +/-");
    Serial.print(d);
    Serial.print("%");

    Serial.println("\n Do you wish to try again? Y or N");
    while (Serial.available() == 0) {}; //Get user input
    Again = Serial.read();  //Store user input
    Serial.println(Again);  //Print user input
  }
  while (Again == 'Y'); // Restart or cancel do loop

  Serial.print("\n Thank you");
  delay(10000);
  Serial.print("\n");
}          //Main Program Ends Here


/*****************************************************************************************************FUNCTION DEFINITIONS*************************************************************************************************************************************************/
3

Watch the data ‘type’s assigned to your variables.

Time to look at what ‘enum’ can do for you:
enum COLOUR{black, brown, red, orange, yellow, green, blue, violet, grey, white}
COLOUR colourSelected;

Then look at switch/case

Using do/while quite often gets new people into trouble, suggest you avoid using them.

4

integer values are 16 bits which go up to 65535 which is why values of 10M don't work. use long

i suggest you creates a subfunction to translate a color code into a numeric value rather than duplicate code. you can use pow() to translate the 3rd value into a multiplier.

you have gold and silver cases for your 3rd color that set an integer, c, to a float value. i don't believe the 3rd color can be gold or silver.