Elevator itself for tysciman7

-- * modem side here
rednet.open("top")

-- * current floor - might not be accurate
-- * since you have three computers (the ones that call the elevator),
--   you could use some GPS code to determine the current floor
local current = 1

local floorIDs = {
    -- * ["sender IDs in strings"] = the floors they are on
    -- * you can expand this table further
    ["40"] = 1,
    ["41"] = 2,
    ["42"] = 3,
}

local gotoFloor = function(target)
    repeat
        if current > target then -- target is lower ...
            for i = 1, 12 do -- ... so go down
                rs.setOutput("right", true)
                sleep(0.5)
                rs.setOutput("right", false)
                sleep(0.5)
                rs.setOutput("back", true)
                sleep(0.5)
                rs.setOutput("back", false)
                sleep(0.5)
            end
            current = current - 1
        elseif current < target then -- target is higher ...
            for i = 1, 12 do -- ... so go up
                rs.setOutput("left", true)
                sleep(0.5)
                rs.setOutput("left", false)
                sleep(0.5)
                rs.setOutput("buttom", true)
                sleep(0.5)
                rs.setOutput("buttom", false)
                sleep(0.5)
            end
            current = current + 1
        end
    until target == current -- we've reached the target
end

while true do
    local eventData = {os.pullEvent()}
    -- * now eventData[2] is the sender and eventData[3] is the message
    if eventData[1] == "rednet_message" and eventData[3] == "elevator_call" then
        -- * every computer will send only "elevator_call"
        local target = floorIDs[tostring(eventData[2])]
        if target then
            -- * call gotoFloor only if target is not nil
            -- * that would mean that a computer which is not in the floorIDs table
            --   above sent the "elevator_call" message
            gotoFloor(target)
        end
    end
end