controlling 4 servos with joystick through python and arduino

Hi guys,
I have hooked up 4 servos to the arduino uno board and found some code from our friends at the principia lab for python to control axis movement from joystick to servos and a short script that gets uploaded to the uno board.
I was wondering if anyone knows how to add trim control.
I want to be able to select different servos from the joystick buttons and adjust trim via two arrow buttons on the joystick.
Currently I am using my brothers forum login as I am new to all this arduino electronics, so please, if anyone knows how to help me with my project it will be much appreciated. Cheers for your help and time.

Here is the link to the lab where I got the code as well as being attached below. [url=http://principialabs.com/arduino-python-4-axis-servo-control/]principialabs.com/arduino-python-4-axis-servo-control/
[/url]

This is the code for the arduino board. Text is red.



[color=red]* ------------------------------
* MultipleSerialServoControl
* ------------------------------
*
* Uses the Arduino Serial library
* ([url=http://arduino.cc/en/Reference/Serial]http://arduino.cc/en/Reference/Serial[/url])
* and the Arduino Servo library
* ([url=http://arduino.cc/en/Reference/Servo]http://arduino.cc/en/Reference/Servo[/url])
* to control multiple servos from a PC using a USB cable.
*
* Dependencies:
* Arduino 0017 or higher
* ([url=http://www.arduino.cc/en/Main/Software]http://www.arduino.cc/en/Main/Software[/url])
* Python servo.py module
* ([url=http://principialabs.com/arduino-python-4-axis-servo-control/]http://principialabs.com/arduino-python-4-axis-servo-control/[/url])
*
* Created: 23 December 2009
* Author: Brian D. Wendt
* ([url=http://principialabs.com/]http://principialabs.com/[/url])
* Version: 1.1
* License: GPLv3
* ([url=http://www.fsf.org/licensing/]http://www.fsf.org/licensing/[/url])
*
*/

// Import the Arduino Servo library
#include <Servo.h>

// Create a Servo object for each servo
Servo servo1;
Servo servo2;
Servo servo3;
Servo servo4;
// TO ADD SERVOS:
// Servo servo5;
// etc...

// Common servo setup values
int minPulse = 600; // minimum servo position, us (microseconds)
int maxPulse = 2400; // maximum servo position, us

// User input for servo and position
int userInput[3]; // raw input from serial buffer, 3 bytes
int startbyte; // start byte, begin reading input
int servo; // which servo to pulse?
int pos; // servo angle 0-180
int i; // iterator

// LED on Pin 13 for digital on/off demo
int ledPin = 13;
int pinState = LOW;

void setup()
{
// Attach each Servo object to a digital pin
servo1.attach(2, minPulse, maxPulse);
servo2.attach(3, minPulse, maxPulse);
servo3.attach(4, minPulse, maxPulse);
servo4.attach(5, minPulse, maxPulse);
// TO ADD SERVOS:
// servo5.attach(YOUR_PIN, minPulse, maxPulse);
// etc...

// LED on Pin 13 for digital on/off demo
pinMode(ledPin, OUTPUT);

// Open the serial connection, 9600 baud
Serial.begin(9600);
pinMode(7,OUTPUT);
digitalWrite(7,LOW);
Serial.println("Slave Ready");
}

void loop()
{
// Wait for serial input (min 3 bytes in buffer)
if (Serial.available() > 2) {
// Read the first byte


startbyte = Serial.read();
// If it's really the startbyte (255) ...
if (startbyte == 255) {
// ... then get the next two bytes
for (i=0;i<2;i++) {
userInput[i] = Serial.read();
}
// First byte = servo to move?
servo = userInput[0];
// Second byte = which position?
pos = userInput[1];
// Packet error checking and recovery
if (pos == 255) { servo = 255; }

// Assign new position to appropriate servo
switch (servo) {
case 1:
servo1.write(pos); // move servo1 to 'pos'
break;
case 2:
servo2.write(pos);
break;
case 3:
servo3.write(pos);
break;
case 4:
servo4.write(pos);
break;

// TO ADD SERVOS:
// case 5:
// servo5.write(pos);
// break;
// etc...

// LED on Pin 13 for digital on/off demo
case 99:
if (pos == 180) {
if (pinState == LOW) { pinState = HIGH; }
else { pinState = LOW; }
}
if (pos == 0) {
pinState = LOW;
}
digitalWrite(ledPin, pinState);
break;
}
}
}
}
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Here is the code for python. Text is green


[color=green]#!/usr/bin/env python

###############################################################################
# Module: multijoystick.py
# Created: 2 April 2008
# Author: Brian D. Wendt
# [url=http://principialabs.com/]http://principialabs.com/[/url]
# Version: 0.4
# License: GPLv3
# [url=http://www.fsf.org/licensing/]http://www.fsf.org/licensing/[/url]
'''
Provides four-axis joystick servo control from a PC
using the Arduino "MultipleSerialServoControl" sketch
and the Python "servo.py" serial abstraction module.

This code was adapted from:
[url=http://svn.lee.org/swarm/trunk/mothernode/python/multijoy.py]http://svn.lee.org/swarm/trunk/mothernode/python/multijoy.py[/url]

Dependencies:
pyserial - [url=http://pyserial.sourceforge.net/]http://pyserial.sourceforge.net/[/url]
pygame - [url=http://www.pygame.org/]http://www.pygame.org/[/url]
servo - [url=http://principialabs.com/arduino-python-4-axis-servo-control/]http://principialabs.com/arduino-python-4-axis-servo-control/[/url]
'''
###############################################################################

print "\n================================================"
print " Arduino/Python Servo Controller"
print "================================================"

# Import dependent Python modules
try:
import servo
except:
print "\nPlease ensure that 'servo.py' is installed in the current directory.\n"
quit()
try:
import pygame.joystick
except:
print "\nPlease install the 'pygame' module <http://www.pygame.org/>.\n"
quit()

# Allow for multiple joysticks
joy = []

# Handle joystick event
def handleJoyEvent(e):
# Identify joystick axes and assign events
if e.type == pygame.JOYAXISMOTION:
axis = "unknown"
if (e.dict['axis'] == 0):
axis = "X"
if (e.dict['axis'] == 1):
axis = "Y"
if (e.dict['axis'] == 2):
axis = "Throttle"
if (e.dict['axis'] == 3):
axis = "Z"

# Convert joystick value to servo position for each axis
if (axis != "unknown"):
str = "Axis: %s; Value: %f" % (axis, e.dict['value'])
# Uncomment to display axis values:
#output(str, e.dict['joy'])

# X Axis
if (axis == "X"):
pos = e.dict['value']
# convert joystick position to servo increment, 0-180
move = round(pos * 90, 0)
serv = int(90 + move)
# and send to Arduino over serial connection
servo.move(1, serv)
# Y Axis
if (axis == "Y"):
pos = e.dict['value']
move = round(pos * 90, 0)
serv = int(90 + move)
servo.move(2, serv)
# Z Axis
if (axis == "Z"):
pos = e.dict['value']
move = round(pos * 90, 0)
serv = int(90 + move)
servo.move(3, serv)
# Throttle
if (axis == "Throttle"):
pos = e.dict['value']
move = round(pos * 90, 0)
serv = int(90 + move)
servo.move(4, serv)

# Assign actions for Button DOWN events
elif e.type == pygame.JOYBUTTONDOWN:
# Button 1 (trigger)
if (e.dict['button'] == 0):
print "Trigger Down"
# Set pin 13 LED to HIGH for digital on/off demo
servo.move(99, 180)
# Button 2
if (e.dict['button'] == 1):
print "Button 2 Down"
# Button 3
if (e.dict['button'] == 2):
print "Button 3 Down"
# Button 4
if (e.dict['button'] == 3):
print "Button 4 Down"
# Button 5
if (e.dict['button'] == 4):
print "Button 5 Down"
# Button 6
if (e.dict['button'] == 5):
print "Button 6 Down"
quit()

# Assign actions for Button UP events
elif e.type == pygame.JOYBUTTONUP:
# Button 1 (trigger)
if (e.dict['button'] == 0):
print "Trigger Up"
# Set pin 13 LED to LOW for digital on/off demo
servo.move(99, 0)
# Button 2
if (e.dict['button'] == 1):
print "Button 2 Up"
# Button 3
if (e.dict['button'] == 2):
print "Button 3 Up"
# Button 4
if (e.dict['button'] == 3):
print "Button 4 Up"
# Button 5
if (e.dict['button'] == 4):
print "Button 5 Up"
# Button 6
if (e.dict['button'] == 5):
print "Button 6 Up"

# Assign actions for Coolie Hat Switch events
elif e.type == pygame.JOYHATMOTION:
if (e.dict['value'][0] == -1):
print "Hat Left"
servo.move(4, 0)
if (e.dict['value'][0] == 1):
print "Hat Right"
servo.move(4, 180)
if (e.dict['value'][1] == -1):
print "Hat Down"
if (e.dict['value'][1] == 1):
print "Hat Up"
if (e.dict['value'][0] == 0 and e.dict['value'][1] == 0):
print "Hat Centered"
servo.move(4, 90)

else:
pass

# Print the joystick position
def output(line, stick):
print "Joystick: %d; %s" % (stick, line)

# Wait for joystick input
def joystickControl():
while True:
e = pygame.event.wait()
if (e.type == pygame.JOYAXISMOTION or e.type == pygame.JOYBUTTONDOWN or e.type == pygame.JOYBUTTONUP or e.type == pygame.JOYHATMOTION):
handleJoyEvent(e)

# Main method
def main():
# Initialize pygame
pygame.joystick.init()
pygame.display.init()
if not pygame.joystick.get_count():
print "\nPlease connect a joystick and run again.\n"
quit()
print "\n%d joystick(s) detected." % pygame.joystick.get_count()
for i in range(pygame.joystick.get_count()):
myjoy = pygame.joystick.Joystick(i)
myjoy.init()
joy.append(myjoy)
print "Joystick %d: " % (i) + joy[i].get_name()
print "Depress joystick button 6 to quit.\n"

# Run joystick listener loop
joystickControl()

# Allow use as a module or standalone script
if __name__ == "__main__":
main()
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