[How to guide] GPS Global Position System

shell.run("gps","host",x,y,z)

shell.run("gps","host",0,3,255)

abc, on 03 August 2012 - 08:12 PM said:

you only need 3 computers, if you look at the gps code it can narrow a position based on only 3 positions and distances
also i have a program to scramble or crash recon turtles so PM me if you plan on having a huge turtle battle

FuzzyPurp, on 29 August 2012 - 08:13 PM said:

Nice work BST- alot of people will appreciate this, including myself.

FuzzyPurp, on 04 September 2012 - 12:21 PM said:

I think Direwolf used your design in his SMP-LP ep 51 :D/>/>

modem_range=64

Slye, on 07 September 2012 - 05:32 AM said:

Thanks for the guide. :D/>/>

When I tried this I saw the note "at the top of the world". Never mind for a moment that you call the up down axis Z (which is cartesian coords as I learned them) and minecraft calls this Y…I went up to about Y=250 and placed this GPS server set up. When I got back down and tried "gps locate" in a computer, it was unable to receive anything from the servers.

I went looking and found this in configs/mod_ComputerCraft.cfg:

modem_range=64

When I changed this to 192, everything worked and I was able to "gps locate". So I'm wondering how you got this server farm to work? Am I missing something important like wraparound vis 8-bits or something?

BigSHinyToys, on 07 September 2012 - 06:04 AM said:

you are not using the most resent version of computer craft. Computers range increases the higher they are. also dan200 doesn't recommend using the "real world" coordinates and recommends that "Relative coordinates" be used instead. the reason that minecraft uses Y for the X axis is because it allows the game to some rendering shortcuts saving CPU time. I might add that the F3 is for debugging not for finding location and will most likely be removed in time.

Slye, on 07 September 2012 - 06:22 AM said:

Relative coordinates? So … where do you get those if not from the information in F3?

Do you mean keeping track of where your turtle moves and letting the origin be where you started the turtle?

Lyqyd, on 20 November 2012 - 02:58 PM said:

For the purposes of a tutorial, it would be better to use Minecraft's (significantly more sensible) coordinate system and axis assignments. Preventing confusing amongst the readers is more important in a tutorial setting than promulgating your own opinions on which axis should be what.

tiin57, on 20 November 2012 - 04:18 PM said:

You do realize that the picture is completely backwards, right?

leftyisgod, on 13 December 2012 - 03:29 PM said:

I have a redpower mobile quarry with an attatched computer and modem. I also have a gps tower set up. I would like to make the computer send a pulse to a specified bundled cable color (diff color wire to a diff frequency to each motor moving the quarry) could someone give me an example on the ways/ codes to do this? i have done simple programs but not anything this big. Thank you for any help

function showInfo()
shell.run('clear')
print("Quarry control center 1.0")
print("-------------------------")
print("Commands:")
print("dig, moveto")
print("------------------------------------")
end

showInfo()

------------------------------------
local cableside = "back"
local up		= colors.yellow
local down	  = colors.red
local left	  = colors.orange
local right	 = colors.pink
local forwards  = colors.black
local backwards = colors.white
local digblocks = colors.blue
------------------------------------

function noOutput()
rs.setBundledOutput(cableside, 0)
end

------------------------------------

function move(direction, amount, bBreak)
amount = amount or 1
bBreak = bBreak or false
for i=1,amount do
  if bBreak == true then
   rs.setBundledOutput(cableside, digblocks)
   sleep(0.1)
  end
  rs.setBundledOutput(cableside, direction)
  sleep(0.1)
  noOutput()
  sleep(1.8)
end
end

------------------------------------

function moveTo(x, y, z)
local xc, yc, zc = gps.locate(3)
local xm = x-xc
local ym = y-yc
local zm = z-zc

if xm > 0 then
  move(backwards, xm)
elseif xm < 0 then
  move(forwards, -xm)
end

if ym > 0 then
  move(up, ym)
elseif ym < 0 then
  move(down, -ym)
end

if zm > 0 then
  move(left, zm)
elseif zm < 0 then
  move(right, -zm)
end
end

------------------------------------

function dig(blocks)
while true do
  move(left, blocks-5, true)
  move(down, 1, true)
  move(right, blocks-5, true)
  move(down, 1, true)
end
end

------------------------------------

while true do
local input = read()

if input == "dig" then
  write("size=")
  local size = read()
  dig(size*6)

elseif input == "moveto" then
  write("x=")
  local tx = read()
  write("y=")
  local ty = read()
  write("z=")
  local tz = read()

  moveTo(tx, ty, tz)
end

showInfo()
end

------------------------------------

shell.run('clear')

BigSHinyToys, on 29 August 2012 - 12:50 PM said:

This is a Experimental and possibly bug riddled code

GPS builder turtle program.

This program sends a turtle up as far as it can go then builds a GPS cluster


Instructions < Reed

[WARNING] This is experimental code there are probably bugs and errors in it you may loose items when using this. I give no Warner to this code. use at your own risk

if you already have working GPS in your world DON'T USE THIS it will cause you a Big problems

I would recommended tying this out in a New creative world before using it in a real survival world so you know what is does.

place a turtle can be mining or normal WIFI not required.


place turtle with a clear path to the sky (no trees or obstacle above it)

add 600 fuel (one bucket of lava is 1200)
add 4 computers to slot 1
add 4 wifi modems to slot 2
If you are using a Mining turtle then you only need one disk drive in slot 3 and you will get it back. if you are not using a mining turtle then you will need four disk drives in slot 3
place a BLANK disk in slot 4


RUN this program.

Spoiler

if not turtle then
print("Error Not turtle")
return
end
if turtle.getFuelLevel() < 600 then
print("600 fuel is required")
return
else
print("Please Place 4 computers in slot one")
print("4 modems in slot two")
print("Disk drive in slot three")
print("and boot disk in slot four")
print("press Enter key to continue")
while true do
  local event , key = os.pullEvent("key")
  if key == 28 then break end
end
print("Launching")
end
local set = {}
set[1] = {x = 0,y = 3,z = 255}
set[2] = {x = 3,y = 0,z = 252}
set[3] = {x = 0,y = -3,z = 255}
set[4] = {x = -3,y = 0,z = 252}
while turtle.up() do
end
for a = 1,4 do
for i = 1,2 do
  turtle.forward()
end
turtle.select(1)
turtle.place()
turtle.back()
turtle.select(2)
turtle.place()
turtle.down()
turtle.forward()
turtle.select(3)
turtle.place()
turtle.select(4)
turtle.drop()
-- make disk cusrom
fs.delete("disk/startup")
file = fs.open("disk/startup","w")
file.write([[fs.copy("disk/install","startup")]])
file.close()
file = fs.open("disk/install","w")
file.write([[shell.run("gps","host",]]..set[a]["x"]..","..set[a]["y"]..","..set[a]["z"]..[[)]])
file.close()
-- end make disk custom
turtle.turnLeft()
turtle.forward()
turtle.up()
turtle.turnRight()
turtle.forward()
turtle.turnRight()
peripheral.call("front","turnOn")
turtle.down()
turtle.suck()
turtle.select(3)
turtle.dig()
turtle.up()
peripheral.call("front","reboot")
turtle.turnRight()
for i = 1,3 do
  turtle.forward()
end
turtle.turnLeft()
turtle.forward()
if a == 1 or a == 3 then
  for i = 1,3 do
  turtle.down()
  end
elseif a == 2 or a == 4 then
  for i = 1,3 do
  turtle.up()
  end
end
end
while turtle.down() do
end

press Enter when you have it set up correctly and it will fly up into the sky place Computers turn them on and comeback down.

There is no back door into the computers so ounce they are up there they are staying there you can edit there code after this.

all going well your turtle returns with the disk to ground level. Report bugs here and I will hunt them down.

usmc3891, on 04 January 2013 - 12:41 PM said:

I've changed your code a little bit to allow for the minecraft coord system. Because of my very limited coding experience the turtle has to be facing west for the coords to be correct. It will prompt you for the x and z coords first before launching, Tell me what you think :)/>

http://pastebin.com/kiSuDf0Z

DrCeph, on 07 January 2013 - 08:13 PM said:

BSH, thanks for this tutorial mate, really helped clear things up for me!

One observation with the GPS program, I think there may be an offset error with z (vertical):

I launched the turtle from a level where my feet position (y) shows as level 64. However once I've seeded the gps and place a computer/turtle at the same place I launched from, I get a z-coord of 65. If I go down to the lowest bedrock level (i.e only one bedrock block between me and void) feet loc shows as 1 whereas GPS z shows as 2.

Either this is an offset error, or the feet pos in the minecraft debug gives the coord of the block below the feet.

Niederlenz, on 07 February 2013 - 11:50 PM said:

How do I get the coords of my turtle like this?

gps can be used to host a GPS server over rednet, or determine a position using trilateration.
Type "help gpsapi" for help using GPS functions in lua programs.

ex:
"gps locate" will connect to nearby GPS servers, and try to determine the position of the computer or turtle.
"gps host" will try to detemine the position, and host a GPS server if successful.
"gps host 10 20 30" will host a GPS server, using the manually entered position 10,20,30.

Take care when manually entering host positions. If the positions entered into multiple GPS host
are not consisent, the results of locate calls will be incorrect.

Functions in the GPS API:
gps.locate( timeout )

The locate function will send a signal to nearby gps servers, and wait for responses before the timeout. If it receives enough responses to determine this computers position then x, y and z co-ordinates will be returned, otherwise it will return nil. If GPS hosts do not have their positions configured correctly, results will be inaccurate.

ChunLing, on 03 August 2012 - 08:47 PM said:

The GPS api itself doesn't do anything other than figure out positions based on existing positions, but your turtles can also act as GPS hosts themselves once they get their own positions. Because they can also transmit rednet wireless messages, it means that you could have all the turtle positions sent back to a central console from which you can see where they all are, and could even give them new orders on the fly (so to speak).