const int rp = 5,rn=6,lp=10,ln=9; // change these pin numbers if needed int speeds = 255 , low = 100; // change these values if needed void setup() { pinMode(rp,OUTPUT); pinMode(rn,OUTPUT); pinMode(lp,OUTPUT); pinMode(ln,OUTPUT); Serial.begin(9600); } void loop() { if (Serial.available() >0) { char cmd = Serial.read(); //Serial.println(cmd); if (cmd == 'f') { //fwd Serial.println("fw"); analogWrite(rp,speeds); analogWrite(rn , 0); analogWrite(lp , speeds); analogWrite(ln , 0); } else if (cmd == 'b') { //bwd Serial.println("back"); analogWrite(rn,speeds); analogWrite(rp , 0); analogWrite(ln , speeds); analogWrite(lp , 0); } else if (cmd == 'r') { //rt Serial.println("right"); analogWrite(rp, 0); analogWrite(rn , low); analogWrite(lp , speeds); analogWrite(ln , 0); } else if (cmd == 'l') { //lt Serial.println("left"); analogWrite(rp,speeds); analogWrite(rn , 0); analogWrite(lp , 0); analogWrite(ln , low); } else if (cmd == 's') { //stop Serial.println("stop"); analogWrite(rp,0); analogWrite(rn , 0); analogWrite(lp , 0); analogWrite(ln , 0); } else{ //stop Serial.println("stop"); analogWrite(rp,0); analogWrite(rn , 0); analogWrite(lp , 0); analogWrite(ln , 0); } } }