Ironically I had the same problem, because I have the sabertooth too. I figured mine out. First set all of the DIP switches to the OFF position, then arduino code time. Servo.write(120); is backwards (in my case), Servo.writeMicroseconds(1200); is forwards (in my case). Now you have independent control of each motor. This has nothing to do with how far it has gone, so in that case, you would have to get encoders or optical interrupters. I hope to be building an AI/pathfinding robot using this speed controller (2x12). You can adjust the speed accordingly. Oh and by the way I have a serial sample code for you where you can test out the different frequencies
// If you need any help feel free to PM me (simonfrfr) or email me
// at newtonlabs@bellsouth.net
String readString;
#include <Servo.h>
Servo myservo; // create servo object to control a servo
Servo myservo2; // create second servo object
const int left = 10; // left motor's pin on arduino
const int right = 9; // right motor's pin on arduino
void setup() {
Serial.begin(9600);
Serial.println("servo-test-22-dual-input"); // so I can keep track of what is loaded
}
void loop() {
while (Serial.available()) {
char c = Serial.read(); //gets one byte from serial buffer
readString += c; //makes the string readString
delay(2); //slow looping to allow buffer to fill with next character
}
if (readString.length() >0) {
Serial.println(readString); //so you can see the captured string
if (readString == "l") // acfivates left servo only
{
myservo.attach(left); // writing both to left motor
myservo2.attach(left);
}
if (readString == "r") // activates right servo only
{
myservo.attach(right); // writing both to left motor
myservo2.attach(right);
}
if (readString == "b") // activates both motors
{
myservo.attach(left); // writing to left motor
myservo2.attach(right); // writing to right motor
}
int n = readString.toInt(); //convert readString into a number
// auto select appropriate value, copied from someone elses code.
if(n >= 500)
{
Serial.print("writing Microseconds: "); // serial display
Serial.println(n); // number
myservo.writeMicroseconds(n); // writes to ports
myservo2.writeMicroseconds(n);
}
else
{
Serial.print("writing Angle: "); // serial display
Serial.println(n); // number
myservo.write(n); // writes to ports
myservo2.write(n);
}
readString=""; //empty for next input
}
}