/*

pin assignments:

10   - base of npn transistor #1 2n2222 (either one)

11  - base of npn transistor #2 2n2222 (the other one…)

*/

int t1 = 10;

int t2 = 11;

void setup(){

pinMode(t1, OUTPUT);

pinMode(t2, OUTPUT);

off();

delay(1000);

}

void loop(){

forward();

delay(10000);

reverse();

delay(10000);

off();

delay(10000);

}

void forward() {

digitalWrite(t1, HIGH);

digitalWrite(t2, LOW);

}

void reverse(){

digitalWrite(t1, LOW);

digitalWrite(t2, HIGH);

}

void off() {

analogWrite(t1, 0);

digitalWrite(t2, HIGH);

}