My main day-to-day computer is my snazzy MacBook Pro that I often hook up on a external display when I arrive at home. The lid is closed as I connect it to the monitor and then I notice I have my bluetooth off and I need it to use my mouse.
Now there are couple of solutions to overcome this serious issue. First off you need a keyboard with a cord. If you also use a bluetooth keyboard these tips won’t help you, but automating the whole process with ControlPlane could.
Solution #1: Bluetooth File Exchange
This one requires no extra software. Simply use your Spotlight-search keyboard shortcut, type “bluetooth” and you should see an application called Bluetooth File Exchange. Hit enter and the application turns your bluetooth on. You can quit the app after this.
This is not the most elegant solution. It is more of a trick than a solution. The main point is that it works and it’s probably only solution you need if you run into this issue only once in a while.
Solution #2: Using Terminal and Blueutil
This solution requires you to install a small free program that is used from the Terminal. The program is called Blueutil and all it does is turn the power or discoverability of bluetooth on or off. This is my preferred method to turn bluetooth on and off when I only have a keyboard.
Original Blueutil can be found from http://www.frederikseiffert.de/blueutil. There is a slightly newer fork of the Blueutil in Github. Blueutil can also be installed easily using the Homebrew-pakage manager. Note that all solutions require you to have Xcode installed.
Solution #3: Using ControlPlane
This solution might be interesting to those who like to automate things. ControlPlane is a Mac app that attempts to sense the environment it is based on various factors such as WiFi network name, connected devices and location. When a environment is sensed it triggers user defined actions such as turning bluetooth on.
ControlPlane is a free application.