while true do
  local m = peripheral.wrap("front")
  if m ~= nil then
    print("Jar detected")
    local aspectCount = m.getAspectCount("Herba")
    if aspectCount == 64 then
      print("Jar is full, sending redstone signal.")
      redstone.setOutput("back", true)
      sleep(20)
      print("Stopping redstone signal.")
      redstone.setOutput("back", false)
    else
      print("Jar isn't full. It only has " .. aspectCount .. ".")
    end
  else
    print("No Jar, check again in 60.")
  end
  sleep(60)
end