newFluidTankMonitor

local tank = peripheral.wrap("front")
local amount
local warning = 0.5
local sleepTime = 5



function getTank(tank)
  local tableInfo = tank.getTankInfo("unknown")
  fluidAmount = nil
  fluidCapacity = tableInfo[1].capacity
  local contents = tableInfo[1].contents
  if contents then
    fluidAmount = contents.amount
  end
  return fluidAmount, fluidCapacity
end

while true do
  rs.setOutput("back", false)
  local fluidAmount, fluidCapacity = getTank(tank)
  amount = fluidAmount

  if fluidCapacity == nil then
    print("FluidCapacity in tank is nil. Mabye no tank is found")
  elseif fluidAmount == nil or fluidAmount == 0 then
    rs.setOutput("back", true)
  else
    if fluidAmount / fluidCapacity <= warning then
      rs.setOutput("back", true)
    end
  end
  sleep(sleepTime)
end