My hammerspoon config

init.lua

local usbWatcher = nil

-- This is our usbWatcher function
-- lock when yubikey is removed
function usbDeviceCallback(data)
    -- this line will let you know the name of each usb device you connect, useful for the string match below
    hs.notify.show("USB", "You just connected", data["productName"])
    -- Replace "Yubikey" with the name of the usb device you want to use.
    if string.match(data["productName"], "Yubikey") then
        if (data["eventType"] == "added") then
            hs.notify.show("Yubikey", "You just connected", data["productName"])
            -- wake the screen up, so knock will activate
            -- get knock here http://www.knocktounlock.com
            os.execute("caffeinate -u -t 5")
        elseif (data["eventType"] == "removed") then
            -- replace +000000000000 with a phone number registered to iMessage
            hs.messages.iMessage("+000000000000", "Your Yubikey was just removed from your Work iMac.")
            -- this locks to screensaver
            os.execute("pmset displaysleepnow")
       end
   end
end

-- Start the usb watcher
usbWatcher = hs.usb.watcher.new(usbDeviceCallback)
usbWatcher:start()

with-dcled.lua

-- get a dreamcheeky led screen like this http://dreamcheeky.com/led-message-board
-- get dcled from here https://github.com/kost/dcled

local usbWatcher = nil

-- This is our usbWatcher function
-- lock when yubikey is removed
function usbDeviceCallback(data)
    hs.notify.show("USB", "You just connected", data["productName"])
    -- Replace "Yubikey" with the name of the usb device you want to use.
    if string.match(data["productName"], "Yubikey") then
        if (data["eventType"] == "added") then
            hs.notify.show("Yubikey", "You just connected", data["productName"])
            -- wake the screen up, so knock will acti
            os.execute("caffeinate -u -t 5")

            setDcled('! BUSY ! BUSY ! BUSY ')
        elseif (data["eventType"] == "removed") then
            -- replace +000000000000 with a phone number registered to iMessage
            hs.messages.iMessage("+000000000000", "Your Yubikey was just removed from your Work iMac.")
            setDcled('THE DEV IS OUT')
            -- this locks to screensaver
            os.execute("pmset displaysleepnow")
       end
   end
end

-- Start the usb watcher
usbWatcher = hs.usb.watcher.new(usbDeviceCallback)
usbWatcher:start()

local dcmenubar = hs.menubar.new()
function setDcled(message)
        dcmenubar:setTitle("led: " .. message)
        hs.notify.show("dcled", "set:", message)
        -- os.execute("ps -ef | grep dcled | grep -v grep | awk '{print $2}' | xargs kill -9")
        os.execute("pkill -9 dcled")
        os.execute('/usr/local/bin/dcled -s 30 --repeat -m \'' .. message  .. '\' &')
end
hs.hotkey.bind({"cmd"}, "f4", function() setDcled('BUSY    <---- SEE RUPERT ') end)
hs.hotkey.bind({"cmd"}, "f5", function() setDcled(':)   :)    :)') end)
hs.hotkey.bind({"cmd"}, "f6", function() setDcled('IN A MEETING') end)
hs.hotkey.bind({"cmd"}, "f7", function() setDcled('LUNCH') end)
hs.hotkey.bind({"cmd"}, "f8", function() setDcled('THE DEV IS OUT') end)

hs.hotkey.bind({"cmd"}, "f9", function() setDcled('THE DEV IS IN') end)
hs.hotkey.bind({"cmd"}, "f10", function() setDcled('! BUSY ! BUSY ! BUSY ') end)
hs.hotkey.bind({"cmd"}, "f11", function() setDcled(' !!! FIXING A CRITICAL BUG !!! DO NOT INTERUPT  ') end)
hs.hotkey.bind({"cmd"}, "f12", function() setDcled(' !!! DO NOT INTERUPT  ') end)