Mega 2560
I am reading in values from 3 pots then mapping them to values between 0 - 255
#define REDPIN 7
#define GREENPIN 8
#define BLUEPIN 9
int red_pot = A0; // analog pin used to connect the potentiometer
int green_pot = A1;
int blue_pot = A3;
void setup() {
pinMode(REDPIN, OUTPUT);
pinMode(GREENPIN, OUTPUT);
pinMode(BLUEPIN, OUTPUT);
Serial.begin(38400); //Debug port
Serial.setTimeout(50);
}
void loop() {
int red, green, blue;
red = analogRead(red_pot);
green = analogRead(green_pot);
blue = analogRead(blue_pot);
Serial.print(" r = ");
Serial.print(red);
Serial.print(" b = ");
Serial.print(blue);
Serial.print(" g = ");
Serial.print(green);
Serial.print("\n\n\n");
// map values
red = map(red, 20, 650, 0, 255);
green = map(green, 20, 570, 0, 255);
blue = map(blue, 20, 570, 0, 255);
Serial.print("red map : ");
Serial.print(red);
Serial.print(" green map : ");
Serial.print(green);
Serial.print(" blue map : ");
Serial.print(blue);
Serial.print('\n\n\n');
analogWrite(REDPIN, red);
analogWrite(GREENPIN, green);
analogWrite(BLUEPIN, blue);
}
red & green behave as expected but blue is not, from the serial monitor...
When blue is at its lowest value,
When blue is at its highest value,
I have changed blue's analog pin assignment but the same issue.
Any clues what's happening?
EDIT #1
I thought it might be some int sign error so I changed the map operation to,
blue = map(abs(blue), 20, 670, 0, 255);
It made no difference.