LED RGB from Serial using PWM

Other Hardware LEDs and Multiplexing
1

Hi,

I'm new in this forum and in Arduino World. I try to change RGB color with the function analogWrite.
My purpose is to send an array like [X,Y,Z] where {X,Y,Z}={0-255,0-255,0-255} to set the different color in real time with serial port communication using Bluetooth.
I tried to set the intensity color to each color and it's OK, but when I add another color it isn't work :frowning:
Below I attach my code for only one led...someone can help me?

int ledB=9;
int VarByte;
char VarText;
void setup(){
pinMode(ledB,OUTPUT);
Serial.begin(115200);
}

void loop(){
if(Serial.available()>0){
VarByte= Serial.read();
VarTesto*=char(VarByte);*

  • analogWrite(ledB, VarText);*
  • }*
2

So you are sending three bytes to go to Red, Green, and Blue PWM channels?

const  int ledRpin=3;  // Pin number for Red PWM
const  int ledGpin=5;  // Pin number for Green PWM
const  int ledBpin=9;  // Pin number for Blue PWM

void setup()
    {
    pinMode(ledRpin,OUTPUT); 
    pinMode(ledGpin,OUTPUT); 
    pinMode(ledBpin,OUTPUT); 
    Serial.begin(115200);
    }

void loop()
   {
   if (Serial.available() >= 3)
      {
      analogWrite(ledRpin, Serial.read());
      analogWrite(ledGpin, Serial.read());
      analogWrite(ledBpin, Serial.read());
      }
   }

You will have a problem if you EVER miss a byte because you have no indication of start and end of groups of three. Because the three data bytes can be any value it will be hard to add framing without splitting the data values across multiple bytes an putting them back together when received.

3

Arrays are not referenced by magic. You have to say which element of the array you are using!

   int led[]={9,10,11};  
   int inByte[3];
        
   void setup(){
     for(int i=0;i<2;i++){           ////  Only two if the three???
        pinMode(led,OUTPUT);     ////  not led[i] ????
        Serial.begin(115200);
       }
   }
  void loop(){
     if(Serial.available()>0){           /// testing for >0 only allows you to read 1 byte safely.  If you read more you might get -1 (no data in buffer)
        for(int i=0;i<3;i++){
             inByte = Serial.read();      ///  not inByte[i] ???
           analogWrite(led,inByte);    /// not led[i] or inByte[i] ???
         } 
       }
    }
4 
if(Serial.available()>0){
        for(int i=0;i<3;i++){
             inByte = Serial.read(); 
           analogWrite(led,inByte); 
}

And if Serial.available () returns 1?

5

BlueEyes:
Yeah, you're right I wrote it in a hurry, but I assure you that the Firmware was right and....it didn't work

So what does the code look like now that you have fixed it and it still doesn't work? Perhaps there is a mistake that you don't recognize.

6

BlueEyes:
Searching I found this library: Arduino Playground - HomePage.

According to you, can be used for this purpose?? It seems interesting...

Yes, just change the callback function to:

void messageReady() {
    analogWrite(9, message.readInt());
    analogWrite(10, message.readInt());
    analogWrite(11, message.readInt());
}

Your sending program will have to send values in ascii decimal separated by spaces and ending with a CR:

"255 0 0\r" = Pin 9 on full, pins 10 and 11 off.
"128 128 255\r" = Pins 9 and 10 at half power, Pin 11 on full.