The pot at the speed pot pin determines the overall speed (forwards and backwards might be asymmetric! The pot at the direction pot pin determines the direction. * all the way down: full speed backward * down: backwards * middle: stop * up: forwards * all the way up: full speed forward

Control Continous Servo with 2 Pots

#include <Servo.h>

int servoPin = 9, speedPotPin = A0, directionPotPin = A1;
Servo servo;
void setup()
{
  Serial.begin(9600);
  pinMode(servoPin, OUTPUT);
  pinMode(speedPotPin, INPUT);  
  pinMode(directionPotPin, INPUT);  
  servo.attach(servoPin);
}

void loop()
{
  int dir = analogRead(directionPotPin);
  int speedVal = analogRead(speedPotPin);
  if(dir < 300) //BACKWARDS
  {
    servo.attach(servoPin);
    int servoSetting = 0;
    if(dir < 100)
    {
      servoSetting = 0;
    }
    else
      servoSetting = map(speedVal, 0, 1024, 90, 0);
    Serial.println(servoSetting);
    servo.write(servoSetting);
  }
  else if( dir > 700) //FORWARDS
  {
    servo.attach(servoPin);
    int servoSetting = 0;
    if(dir > 900)
    {
      servoSetting = 180;
    }
    else
      servoSetting = map(speedVal, 0, 1024, 90, 180);
    Serial.println(servoSetting);
    servo.write(servoSetting);
  }
  else //STOP
  {
    servo.detach();
  }

  delay(100); 
}