cartReturn

local hasCart = false
local dector = peripheral.wrap("top")

while (true)
do
    if (dector.isPlayersInRange(5))
    then
        hasCart = true
    elseif (hasCart)
    then
        hasCart = false
        redstone.setOutput("back", true)
        os.sleep(0.5)
        redstone.setOutput("back", false)
    end
    os.sleep(0.5)
end