Issue with Serial Data when Trying to Light Up 5 LEDS

Using Arduino Project Guidance
#1

Hello All,

I am very new to this, and I am trying my best to post this question appropriately given that another user was kind of rude when I didn’t properly format my post.

Anyhow, here’s the problem. I have a 5 LED set up. I have five different scenarios in the code. When I enter a number between 1 and 100, I want them to light up based on how close to 100 I am. For instance, when I enter 60, I want three LEDs to light up…at 80…four will light up.

The code I wrote is accepted by the Arudino. When I press 1…1 LED lights up. If I press 0…all go dim. However, when I enter any number higher than 1, nothing else happens. I took a look at my serial data. When I enter the number 0, I see that the number 48 appears on the serial data screen. If I press 1, it shows up as 49…and so on and so forth between numbers 1 through 10.

Any help? Here is my code:

const int ledPin1 = 9;
const int ledPin2 = 10;
const int ledPin3 = 11;
const int ledPin4 = 12;
const int ledPin5 = 13;

void setup() {
  // put your setup code here, to run once:

  Serial.begin(9600);
 
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(ledPin3, OUTPUT);
  pinMode(ledPin4, OUTPUT);
  pinMode(ledPin5, OUTPUT);

  int value = 0;
  
}

void loop()

{

int value;

if(Serial.available())

{

delay(50);

while(Serial.available() >0)

{

value=Serial.read();
  
Serial.println(value, DEC);
  

  
if(value<='99' && value>='80'){
digitalWrite(13,HIGH);
digitalWrite(12,HIGH);
digitalWrite(11,HIGH);
digitalWrite(10,HIGH);
digitalWrite(9,HIGH);

}

else if(value<='79' && value>='60'){
digitalWrite(13,HIGH);
digitalWrite(12,HIGH);
digitalWrite(11,HIGH);
digitalWrite(10,HIGH);
digitalWrite(9,LOW);

}

else if(value<='59' && value>='40'){
digitalWrite(13,HIGH);
digitalWrite(12,HIGH);
digitalWrite(11,HIGH);
digitalWrite(10,LOW);
digitalWrite(9,LOW);
  
}
  
else if(value<='39' && value>='20'){
digitalWrite(13,HIGH);
digitalWrite(12,HIGH);
digitalWrite(11,LOW);
digitalWrite(10,LOW);
digitalWrite(9,LOW);
  
}
  
else if(value<='19' && value>='1'){
digitalWrite(13,HIGH);
digitalWrite(12,LOW);
digitalWrite(11,LOW);
digitalWrite(10,LOW);
digitalWrite(9,LOW);
  
}

  
else {
  
digitalWrite(13, LOW);
digitalWrite(12,LOW);
digitalWrite(11,LOW);
digitalWrite(10,LOW);
digitalWrite(9,LOW);

} 
  
  
}
  
}
}
#2

Serial data comes as ASCII, see www.asciitable.com

So you need to subtract 48 from every byte received, and then combine 2 or 3 bytes into one number (value) if you're expecting 0 to 100.
So '0' comes in as 48, so subtract 48.
1,2,3,4,5,6,7,8,9 come in as 49, 50, 51, etc.

value then is byte0 * 100 + byte 1 * 10 + byte 2 to result in 0 to 100.

#3

You also need to modify your if() statements. Things inside a single quote are 1 char so things like '80' or '60' don't make sense. After you get your input converted to a number, just use numbers in the if() statements

#4

Hello All,

So this works for numbers 1 through 9:

value = Serial.read() - '0';

Then I added this so that I could get numbers 10 through 99 :

value = Serial.read() - '0';
  
  
value2 = Serial.read() - '0';

Serial.println(value && value2);

Any further guidance is very much appreciated!

#5

'&&' is the logical and operator. The value you want is value * 10 + value2

You also need to check if there is a char available to read() before just blindly doing so. In the world of Arduino, the serial input is VERY slow and often doesn't become available all at once.

#6

That worked perfectly! Thank you very much.

#7