Energy cell power monitor

--Monitors power storage devices such as TE3 Energy cells and output redstone signals once energy storage drops below set limits.
--Building guide(looking at the front of the devices):
-- MM
-- EC

-- M: Monitor, E: Energy storage device, C: Computer
-- Redstone signal for the engines will be output out the back of the computer.

-- More details: http://forum.feed-the-beast.com/threads/rhns-1-6-monster-build-journal-and-guide-collection.42664/page-15#post-718973


local monitor = peripheral.wrap("top")
local cell = peripheral.wrap("left")
local upper = 0.90 --Upper limit for computer to stop transmitting redstone signal. 0.90=90% full.
local lower = 0.10 --Lower limit for computer to start transmitting redstone signal.



redstone.setOutput("back", false) --Defaulting to off

    monitor.clear()
    monitor.setBackgroundColour((colours.grey))
    monitor.setCursorPos(1,4)
    monitor.write(" ON ")
    monitor.setBackgroundColour((colours.green))
    monitor.setCursorPos(5,4)
    monitor.write(" OFF ")
    monitor.setBackgroundColour((colours.black))


while true do
    eNow = cell.getEnergyStored("left")
    eMax = cell.getMaxEnergyStored("left")

    fill = (eNow / eMax)


    monitor.setCursorPos(11,2)
    monitor.write("Storage:")
    monitor.setCursorPos(11,3)
    monitor.write(eNow)
    monitor.setCursorPos(11,4)
    monitor.write("Of:")
    monitor.setCursorPos(11,5)
    monitor.write(eMax)

    monitor.setCursorPos(1,2)
    monitor.write("Engines:")


    if fill > upper then
        --energylevel is over upper level, turning redstone signal off
        redstone.setOutput("back", false)
        monitor.setBackgroundColour((colours.grey))
        monitor.setCursorPos(1,4)
        monitor.write(" ON ")
        monitor.setBackgroundColour((colours.green))
        monitor.setCursorPos(5,4)
        monitor.write(" OFF ")
        monitor.setBackgroundColour((colours.black))

    elseif fill < lower then
        --energy level is below lower limit, turning redstone signal on
        redstone.setOutput("back", true)
        monitor.setBackgroundColour((colours.green))
        monitor.setCursorPos(1,4)
        monitor.write(" ON ")
        monitor.setBackgroundColour((colours.grey))
        monitor.setCursorPos(5,4)
        monitor.write(" OFF ")
        monitor.setBackgroundColour((colours.black))
    end


    sleep(1)
end --while