Auto TNT Placer

local tntTimer

function init()
    tntTimer = os.startTimer(300)
    placeBlock()
    while true do
      local event, timerID = os.pullEvent("timer")
      if ( event == "timer" and timerID == tntTimer ) then
        placeBlock()
        tntTimer = os.startTimer(300)
      end
    end
end

function placeBlock()
    rs.setOutput('back', true)
    sleep(0.5)
    rs.setOutput('back', false)
end

init()