Simple awesome battery widget for notebooks with SMAPI (IBM/Lenovo).

gistfile1.lua

-- register widget
batterywidget = widget({type = "textbox", name = "batterywidget", align = "right" })

-- timer
awful.hooks.timer.register(10, function()
  battery('BAT0')
end)

-- widget function
function battery(adapter)
    spacer = " "
    local fcur = io.open("/sys/devices/platform/smapi/"..adapter.."/remaining_percent")    
    local fsta = io.open("/sys/devices/platform/smapi/"..adapter.."/state")
    local cur_percent = tonumber(fcur:read())
    local sta = fsta:read()
    fcur:close()
    fsta:close()

    if sta:match("discharging") then
        dir = "↘"
        if cur_percent < 20 then
            color = "orange"
        elseif cur_percent < 7 then
            color = "red"
            naughty.notify({ title      = "Battery Warning",
                text       = "Battery low!"..spacer..cur_percent.."%"..spacer.."left!",
                timeout    = 5,
                position   = "top_right",
                fg         = beautiful.fg_focus,
                bg         = beautiful.bg_focus
            })
        end
    elseif sta:match("charging") then
        dir = "↗"
        color = "green"
    else
        dir = ""
        color = nil
    end

    widget_text = spacer..cur_percent.."%"..dir..spacer
    if color then
        batterywidget.text = '<span color="'..color..'">'..widget_text.."</span>"
    else
        batterywidget.text = widget_text
    end
 end