Spawner

local modem = peripheral.find("modem")
rednet.open("right")

redstone.setOutput("bottom", true)
while true do
    local sender, message, protocol = rednet.receive("spawner")
    if(message ~= null) then
        print("target time: " .. message)
        redstone.setOutput("bottom", false)
        for i = 0, message, 1 do
            sleep(1)
        end
        redstone.setOutput("bottom", true)
    end
end