You just have to set it up so randpin doesn't change between becoming an output and an input.
int randpin = pins[random(4)];
pinMode(randpin, OUTPUT);
delay(20);
PinMode(randpin,INPUT);
You just have to set it up so randpin doesn't change between becoming an output and an input.
int randpin = pins[random(4)];
pinMode(randpin, OUTPUT);
delay(20);
PinMode(randpin,INPUT);