Hardcode password in a do shell script not working

Question

I have been trying to solve something i have wanted to do for a long time, that is get a script that changes the ammount of time before the display goes to sleep. I tried GUi scripting but in system preferences the changes made to the slider did not stay. So i have now come onto a do shell script. Found below. I would prefer to just hardcode my password into it however this does not seem to work. Any ideas ?
set exitflag to false
try
repeat until exitflag is true
set {text returned:Sleeptime, button returned:sleepstate} to (display dialog "Minutes before display sleep" & return & "Between 1 and 180 mintues" & return & "Greater than 180 means never sleep" default answer "1" buttons {"Cancel", "OK"} default button 2)
set Sleeptime to Sleeptime as number
if Sleeptime is less than 1 then
set exitflag to false
else if Sleeptime is greater than 180 then
set Sleeptime to 0
set exitflag to true
else
set exitflag to true
end if
end repeat
end try
set Sleeptime1 to Sleeptime as string
set Sleeptime1 to quoted form of Sleeptime1
set psswd to quoted form of "XXXXX"
do shell script "sudo pmset -a displaysleep " & Sleeptime1 password psswd
set pete to do shell script "sudo pmset -g"
set xx to text -2 thru -1 of pete
if xx - Sleeptime = 0 then
tell application "SEC Helper"
show screen message "Worked:" & return & xx & " mintues"
end tell
else
tell application "SEC Helper"
show screen message "Failed!"
end tell
end if

Answer 1

1) don't use 'sudo' in a 'do shell script'. It isn't necessary and will sometimes break.
2) do not use 'sudo' in a 'do shell script'
3) do not use... I'm sure you get the idea.
It is not necessary to use 'sudo' in a 'do shell script' command. 'do shell script' itself takes care of the authentication element when you use 'with administrator privileges'. Therefore the appropriate way of doing this is:
<pre class=command>do shell script "pmset -g displaysleep " & sleeptime1 with administrator privileges password psswd</pre>
If you omit the 'password psswd' element the user will be prompted to authenticate using the standard system authentication dialog.
The problem you're running into is that the 'password' parameter is only valid when you use 'with adminitrator privileges', and is therefore getting ignored in your current script.