Reed switch plus RGB led

Projects General Guidance
1

Hi,

Recently I made a code to work with one simple led where it interacts with a reed switch. So when the magnet is nearby, a led produces continuous light, and when the magnet is taken away a led slowly fades out. However, for my final idea, I need a led to fade from yellow to red while fading out completely at the same time. So far I managed to only make yellow and fade it out. Does anyone know how I could adjust the colours while still having this smooth fading out effect?

int ledPinR = 11;
int ledPinG = 10;
int ledPinB = 9;
int reedPin = 2;


int brightness = 0;
int fadeAmount = 5;
unsigned long timestamp = 0;

void setup(){
    pinMode(ledPinR, OUTPUT);
    pinMode(ledPinG, OUTPUT);
    pinMode(ledPinB, OUTPUT);
    pinMode(reedPin, INPUT_PULLUP);
}

void loop(){
    if(millis()-timestamp > 30){
        brightness = brightness - fadeAmount;
        if(brightness < 0) brightness = 0;
        timestamp = millis();
    }

    if(!digitalRead(reedPin)){
        brightness = 255;
    }

    analogWrite(ledPinR, brightness);
    analogWrite(ledPinG, brightness);
}
2

Try using 255 - brightness for the upfading LED. Check for the result being >= 0 and as well <= 255.