#define ledGroen 8
#define ledRood 10

int aanTijd = 100 ;
int knipperIntervalRood = 250;
int knipperIntervalGroen = 500;

unsigned long resetGroen = 0;
unsigned long resetRood = 0;


void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(ledGroen, OUTPUT);
  pinMode(ledRood, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  if ( millis() - resetGroen > knipperIntervalGroen) {
    digitalWrite(ledGroen, ! digitalRead(ledGroen));
    resetGroen = millis();
  }
  if (millis() - resetRood > knipperIntervalRood) {
    digitalWrite(ledRood, ! digitalRead(ledRood));
    resetRood = millis();
  }
}