updating positional data

[Saz]

Hi,

hope you all had a good Christmas and New Year. I am trying to get the joystick position to update on the screen, however instead of updating it merely writes over the previous value resulting in a huge jumbled mess. Would I need to define this process as a separate function?

file = open( 'speed_.txt' + str(subject),'w' )
#Open file in path
#file = open( path + 'speed.txt', 'w' )

def mytimer (num):
	joy_pos = str(joy.getPosition())
	#speed = joy_pos*[0.0,5.0,0.0]
	out = str(joy_pos + '\n')
	file.write(out)
	file.flush()
	print out
	
#Add text to the screen.
	speed = viz.addText(joy_pos, viz.SCREEN)
	speed.setPosition(.05, .9 ) 
	speed.fontSize (30)
	
	speed.message(str(joy_pos))
	
viz.callback( viz.TIMER_EVENT, mytimer )
viz.starttimer( 0, 0.25, viz.FOREVER )

Also as its the joystick position it comes up as an [x, y, z] co-ordinate system whereas I'm only really interested in the y-axis, is there a way around this? Its coded as follows:

def UpdateJoystick():
    #Get the joystick position
    x,y,z = joy.getPosition()
    #Get the twist of the joystick
    twist = joy.getTwist()
    #Move the viewpoint forward/backward based on y-axis value
    if abs(y) > 0.001: #Make sure value is above a certain threshold
        viz.MainView.move(0,0,-y*MOVE_SPEED,viz.BODY_ORI)
    #Move the viewpoint left/right based on x-axis value
    if abs(x) > 0.001: #Make sure value is above a certain threshold
        viz.MainView.move(x*0.1,0,0,viz.BODY_ORI)
    #Turn the viewpoint left/right based on twist value
    if abs(twist) > 0.001: #Make sure value is above a certain threshold
        viz.MainView.rotate(0,1,0,twist,viz.BODY_ORI,viz.RELATIVE_WORLD)

The y position would also need to be multiplied by a value in order to make sense but I'm guessing that's a simple math function?
Any help - as usual will be greatly appreciated!!!