View difference between Paste ID: iESPvWHZ and 3mJYuz45

 local timer = 0.5
 local sensor = peripheral.find("openperipheral_sensor")
 local rsSide = "back"
 
 if sensor == nil then
  error("no sensor found")
 end
 
 function loop()
   local dragon = false
   local mobs = sensor.getMobIds()
 
   --for _,id in pairs(mobs) do
   --  local mob = sensor.getMobData(id)
 
   --  local name = mob.basic().name
 
   --  if name == "Ender Dragon" then
   --    dragon = true
   --  end
   --end
 
   if #mobs > 0 then
     print("Dragon detected")
     rs.setOutput(rsSide, true)
   else
     print("No Dragon found")
     rs.setOutput(rsSide, false)
   end
 end
 
 
 
 os.queueEvent("timer")
 local run = true
 while run do
   local ev, p1, p2, p3 = os.pullEvent()
 
   if ev == "timer" then
     loop()
     os.startTimer(timer)
   end
 
   if ev == "char" and p1 == "t" then
     run = false
   end
 
 end