Mining Turtle

I wanted to do a little mining program.
So i wanted the turtle to dig down which is no problem but i want it to build tunnels at some y-levels.
so my question is, is there a easier way to get the y coordinate than gps.locate ? And when not how does the gps.locate command work ?

Thx for help

You could just enter the Y coordinate manually. A lot of turtle programs I know of (including some I've coded myself) do that.

But i want to set up kind of an automated mining
How should i enter the coordinate manually ?

Other than entering it manually, this is how GPS works.

http://www.computercraft.info/forums2/index.php?/topic/3088-how-to-guide-gps-global-position-system/

http://computercraft.info/wiki/Gps_(API)

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