How to make arduino recognize a pair of numbers and turn on an led.

Projects General Guidance
1

Hello all, the title may be a bit confusing but all I really have is 2 numbers. A rowState which ranges from 1-5 and a columnState which ranges from 1-5. So what my program does is that it first detects if a "row button" is hit. If one of the 5 row buttons are hit then the state of a variable "rowState" changes to either 1-5 depedning on which button you hit. Then it does the same with the columns. Once i hit a row button and a column button i tell my program to print both of the states to see if it works and it does. Now the question is how would I light up a certain led from a 5 by 5 grid (max7219) using those coordinates so to speak. So if rowState = 1 and columnState = 1 and I ultimately want to have the led (1,1) turn on. Any ideas, Im still kind of a beginner in arduino and I'm surprised I got this far with the project so any help is thankfull.

My code is below if anyone was wondering.

#define referenceVoltage A0
#define buttonRow A1
#define buttonColumn A2

#define ledB 2
#define ledC1 3


  int voltage = analogRead(referenceVoltage);
  int whichRow = analogRead(buttonRow);
  
  int rowState = 0;
  int columnState = 0;

void setup()
{
	Serial.begin(9600);
	
}

void loop() {
  
  
  while(rowState == 0){
rowcheck();

}

while(columnState == 0) {
	
	columnCheck();
}
 
 Serial.print("row =");
 Serial.println(rowState);
 Serial.print("column =");
 Serial.println(columnState);
 delay(1000);
 
}

void rowcheck() {
	
	int voltage = analogRead(referenceVoltage);
  int whichRow = analogRead(buttonRow);
	
	if (whichRow > .9*voltage) {
    Serial.println("B");
    rowState = 1;
    delay(250);
  
  } 
  else {
    if (whichRow > .7*voltage) {
Serial.println("I"); 
rowState = 2;
delay(250);
    } 
  else {
    if (whichRow > .5*voltage) {
    Serial.println("N");
    rowState = 3;
    delay(250);
  } 
  else {
    if (whichRow > .3*voltage) {
    Serial.println("G");
    rowState = 4;
    delay(250);
  } 
  else {
    if (whichRow > .1*voltage) {
    Serial.println("O");
    rowState = 5;
    delay(250);
  } 
  else {
    Serial.println("nothin hit");
    delay(250);}
  }
  }
  }
  }
}


void columnCheck() {
	
	int voltage = analogRead(referenceVoltage);
  int whichColumn = analogRead(buttonColumn);
	
	if (whichColumn > .9*voltage) {
    Serial.println("1");
    columnState = 1;
    delay(250);
  
  } 
  else {
    if (whichColumn > .7*voltage) {
Serial.println("2");  
columnState = 2;
delay(250);
    } 
  else {
    if (whichColumn > .5*voltage) {
    Serial.println("3");
    columnState = 3;
    delay(250);
  } 
  else {
    if (whichColumn > .3*voltage) {
    Serial.println("4");
    columnState = 4;
    delay(250);
  } 
  else {
    if (whichColumn > .1*voltage) {
    Serial.println("5");
    columnState = 5;
    delay(250);
  } 
  else {
    Serial.println("nothin hit");
    delay(250);}
  }
  }
  }
  }
	
}
2

Ok, that's easy enough and there are a few ways to do it, but the most common way it to use a container "Packet". You want to send the data as < value1 , value2 >. If the first char is '<', then collect the rest until the serial monitor receives '>'. A comma is a good way to split the data into multiple parts, so you will need that too.

So it would be something like this.

if(Serial.available() > 0){
char temp = Serial.read(); // example incomming data <1,23,456,7890>
if( temp == '<' ) // find this char in the buffer, and start collecting the rest after it.
{
while( true ) // just a loop to continuously gather the rest of the chars
// another Serial.available and Serial.read() here.

//look at the incoming char and see if it is a comma or the end of the container '>'
// if it in not a comma or >, then store the char(s) into a temporary array
// if the char IS a comma then increment the arrays index by 1 to store the next char(s)

// keep doing this until the incoming char is > then break out of the while loop and you should have all your data

I have a working example if you want to take a look at it.

3

So I sort of understand it haha. So the data I'm recieving is rowState and columnState. How would i apply your program to mine. I'm assuming its gonna go after the column check.

4

If you could send me the sample code that would be nice. I'm confused on how all this would work and whats happening where.

5

It doesn't get much more simpler than this.

int buffer[8];
int counter = 0;

void setup()
{
  Serial.begin(115200);
}

void loop() 
{
  if(Serial.available() > 0)
  {
    char temp = Serial.read(); // example incomming data <1,23,456,7890>
    if( temp == '<' ) // is incoming char equal to <, if so gather the rest
    { 
      counter = 0; // make sure counter is set to zero
      while(1)
      {
        if(Serial.available() > 0)
        {
          char temp = Serial.read(); // read in incoming char
          
          if(temp != ',' && temp != '>') 
          {
            buffer[counter] = (buffer[counter]*10) + (temp - '0');// converts temp into an int then stores it
          }

          if(temp == ',') 
          {
            counter++; // increment buffer index
          }

          if(temp == '>') // if incoming char is >, then break out of loop
          {  
            break; // breaks out of the while loop
          }
        }
      }
    }
    for(int NUM = 0; NUM <= counter; NUM++) //will output "1,23,456,7890"
     {
       Serial.print(buffer[NUM]);
       if(NUM != counter) Serial.print(",");
     }
     Serial.println();
  }

  while(counter != -1) // clear the buffer
  {
    buffer[counter] = 0; 
    --counter;
  }
}
6

Simple serial LED on/off code.

// zoomkat 8-6-10 serial I/O string test
// type a string in serial monitor. then send or enter
// for IDE 0019 and later

//A very simple example of sending a string of characters 
//from the serial monitor, capturing the individual 
//characters into a String, then evaluating the contents 
//of the String to possibly perform an action (on/off board LED).

int ledPin = 13;
String readString;

void setup() {
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT); 
  Serial.println("serial on/off test 0021"); // so I can keep track
}

void loop() {

  while (Serial.available()) {
    delay(3);  
    char c = Serial.read();
    readString += c; 
  }

  if (readString.length() >0) {
    Serial.println(readString);

    if(readString.indexOf("on") >=0)
    {
      digitalWrite(ledPin, HIGH);
    }

    if(readString.indexOf("off") >=0)
    {
      digitalWrite(ledPin, LOW);
    }

    readString="";
  } 
}