PlayerDetector

local detector = peripheral.find("playerDetector")
if detector == nil then
    error("playerDetector not in range")
end
function PlayerCheck()
    return detector.isPlayersInRange(3)
end
while true do

    if PlayerCheck() == true then
        redstone.setOutput("top",true)
    else
        redstone.setOutput("top", false) --This one just turns the redstone signal off so it's not kept on after the player leaves
        print("Nope.\n")
    end
sleep(0)
end