local awful = require('awful')
local gears = require('gears')

local function emit_bluetooth_status()
  awful.spawn.easy_async_with_shell(
    "bash -c 'bluetoothctl show | grep -i powered:'", function(stdout)
      local status = stdout:match("yes") -- boolean
      awesome.emit_signal('signal::bluetooth', status)
    end)
end

-- Refreshing
-------------
gears.timer {
  timeout   = 2,
  call_now  = true,
  autostart = true,
  callback  = function()
    emit_bluetooth_status()
  end
}