local users = {["m3ntalpain"] = true,
["phaNnYpacker86"] = true,
["JellieBaby"] = true,
["kellychris200"] = true}
local sensor = peripheral.wrap("right") -- where the sensor is
-- How close you need to be to the sensor in order to use it.
local minX = -2 local maxX = 20
local minY = 0  local maxY = 20
local minZ = -2 local maxZ = 20
-- Initial output
redstone.setOutput("back", true)
while true do
        players = sensor.getPlayerNames()
        -- Don't do checks if there are no players.
        if #players == 0 then
                redstone.setOutput("back", true)
                sleep(0.7)
        else -- There are players
                for _, name in pairs(players) do
                        -- If the users listed in above ( local users ) then output is true.
                        if users[name] then
                                info = sensor.getPlayerData(name)
                                pos = info.position

                                if pos.x >= minX and pos.x <= maxX
                                and pos.y >= minY and pos.y <= maxY
                                and pos.z >= minZ and pos.z <= maxZ then
                                        redstone.setOutput("back", false)
                                        break
                                end
                        end
                end
                -- There are players around, we need to be more responsive
                sleep(0.5)
        end
end