Help Reversing Servos!!!

Using Arduino Programming Questions
1

Can anyone help please? I'm new to code and everything. I have this code for four different servos and I'm needing two of them to be reversed. I need servo 3 and 4 to be reversed or in other words, the mirror image of servo 1 and 2. can someone please help me!
Thank You
Mike

Heres the code:

#include <Servo.h>

Servo servo1; // create servo object to control a servo
Servo servo2; // create servo object to control a servo
Servo servo3; // create servo object to control a servo
Servo servo4; // create servo object to control a servo

int pos1; // angle of servo 1
int pos2; // angle of servo2
int pos3; // angle of servo3
int pos4; // angle of servo4
void setup()
{
servo1.attach(9); // attaches the servo on pin 9 to the servo head object
servo2.attach(10); // attaches the servo on pin 10 to the servo faceplae object
servo3.attach(11); // attaches the servo on pin 11 to the servo faceplate 2
servo4.attach(12); //attaches the servo on pin 12 to the servo head 2
}

void loop()
{
// Scene 1:
for (int i=0; i<45; i += 1) {
pos1 = 90 - i;
pos2 = 90 + (i1);
pos3 = 90 + i;
pos4 = 90 - (i1);

servo1.write(pos1);
servo2.write(pos2);
servo3.write(pos3);
servo4.write(pos4);
delay(15);
}

// Scene 2
for (int i=0; i<60; i += 1) {
pos1 = 170;
pos2 = 180;
pos3 = 170;
pos4 = 180;
servo1.write(pos1);
servo2.write(pos2);
servo3.write(pos3);
servo4.write(pos4);
delay(15);
}
}

2

A servo position will be from zero to 180 degrees when using the servo library, so to produce a mirror image of one servo in relation to another subtract the value written to servo A from 180 and use it for servo B.

Examples
Servo A goes to 45 degrees, servo B goes to 180 - 45 (ie, 135 degrees)
Servo A goes to 180 degrees, servo B goes to 180 - 180 (ie, 0 degrees)
Servo A goes to 90 degrees, servo B goes to 180 - 90 (ie, 90 degrees)
Servo A goes to 100 degrees, servo B goes to 180 - 100 (ie, 80 degrees)

If you are using continuous rotation servos then the number written indicates a speed rather than a position but the principle still holds.

3

MikeVSnead:
Heres the code:

 pos2 = 90 + (i*1);

i*1 will always = i so

 pos2 = 90 + i;

will do exactly the same.

4

To have two servos mirror each other (like continuous rotation servos driving wheels on opposite sides a bot) you can use something like below.

    servo1.write(pos1);
    servo2.write(pos2);
    servo3.write(180-pos1);
    servo4.write(180-pos2);