#include <SoftwareSerial.h>

// Pin 6 is to receive from the controller and does not need to be connected
SoftwareSerial servoController(6, 7);

int pos = 0;

void setup() {
  Serial.begin(9600);
  servoController.begin(9600);
}

void loop() {
  Serial.println(pos);

  // set position for three servos simultaneously
  for(int i=0; i<3; i++) {
    setPosition((byte)i, (byte)pos);
  }
  
  pos++;
  if(pos == 255) {
    pos = 0;
  }

  delay(10);
}

void setPosition(byte servo, byte pos) {
  servoController.write(0xFF);
  servoController.write(servo);
  servoController.write(pos);
}