a battery widget for awesome wm.

battery.lua

-- {{{ Battery bar
mybatterybar = awful.widget.progressbar()
mybatterybar:set_border_color(theme.border_normal)
mybatterybar:set_background_color(theme.bg_normal)
mybatterybar:set_color(theme.bg_focus)
mybatterybar:set_width(50)

mytimer = timer({ timeout = 30 })
mytimer:connect_signal("timeout", function()
                                      f = io.popen('acpi -b', r)
                                      state, percent = string.match(f:read(), 'Battery %d: (%w+), (%d+)%%')
                                      f:close()
                                      percent = tonumber(percent)/100
                                      if state == 'Discharging' then
                                        mybatterybar:set_color('#CCCC00')
                                        if percent < 0.2 then
                                          mybatterybar:set_color(theme.bg_urgent)
                                        end
                                      elseif state == 'Charging' then
                                        mybatterybar:set_color('#66CC00')
                                      else
                                        mybatterybar:set_color(theme.bg_focus)
                                      end
                                      mybatterybar:set_value(percent)
                                  end)
mytimer:start()
mytimer:emit_signal("timeout")
-- }}}