Hello,
I'm passing three values (R,G,B) to Arduino from a Python file (via pyserial) and lighting up the LED included in the starter kit (which I believe is 'common cathode') as discussed in project 4 "Color Mixing Lamp".
Everything is 'working' and the LED shows expected results for values like:
255, 0, 0 - Shows Red
0, 255, 0 - Shows Green
0, 0, 255 - Shows Blue
Some mixed colors however, don't appear as they would, for example, in a color chooser application.
For example the LED output for "19, 235, 26" appears light purple, whereas it should actually appear lime green.
See Online RGB Color Wheel for an example.
Is this a 'known' scenario?
Perhaps if I used more expensive LED's or a RGB led strip, the colors would be more accurate?
Thank You.
Arduino Code
// digital output pin numbers
const int digitalOutputPinForRedLED = 9;
const int digitalOutputPinForGreenLED = 10;
const int digitalOutputPinForBlueLED = 11;
// global variables
int valueOfRed = 0;
int valueOfGreen = 0;
int valueOfBlue = 0;
int x = 1;
void setup() {
// initialize serial communications at 9600 bps:
Serial.begin(9600);
// set digital pin modes
pinMode(digitalOutputPinForRedLED,OUTPUT);
pinMode(digitalOutputPinForGreenLED,OUTPUT);
pinMode(digitalOutputPinForBlueLED,OUTPUT);
}
void loop() {
if (Serial.available()) {
if (x==1) {
valueOfRed = Serial.read();
Serial.print("Red: ");
Serial.println(valueOfRed);
analogWrite(digitalOutputPinForRedLED, valueOfRed);
}
else if (x==2) {
valueOfGreen = Serial.read();
Serial.print("Green: ");
Serial.println(valueOfGreen);
analogWrite(digitalOutputPinForGreenLED, valueOfGreen);
}
else if (x==3) {
valueOfBlue = Serial.read();
Serial.print("Blue: ");
Serial.println(valueOfBlue);
analogWrite(digitalOutputPinForBlueLED, valueOfBlue);
}
x++;
}
else {
x = 1;
}
delay(1);
}
Python Code
import serial
import struct
ser = serial.Serial('/dev/ttyACM0', 9600)
red_value = int(request.GET.redvalue)
green_value = int(request.GET.greenvalue)
blue_value = int(request.GET.bluevalue)
ser.write(struct.pack('>3B', red_value, green_value, blue_value))
