i suggest you learn the PAWN basics
![Cheesy](images/smilies/biggrin.png)
okay lol here we go xD
1. make your object
2. make a public that will get the players pos and
3.
check if it's withing the gate's opening range (using PlayerToPoint or u could use IsPlayerInArea..)
PlayerToPoint checks if the player is at a distance to 1 given point
IsPlayerInArea checks if the player is in a specified "square" (there are also some things like "IsPlayerInCube")
4. then also if "it's true" make happen the gate opens (using MoveObject)
- also forward the public!!(forward publicname(something you got in the public at this place...);
5. put somewhere a timer (for the public that will check the pos.. i recommend 5631 (random value and its a 5,6 sec check)
no
6. should work now...
EDIT:
BTW found this(if this will not help you here under you have an EXACT explanation of all things you need to know)
http://forum.sa-mp.com/index.php?topic=54701.0